[解決済み】Brewのアップデートに失敗：追跡されていないワーキングツリーファイルがマージによって上書きされる可能性がある

質問

でHomebrewをアップデートしようとしています。 brew update 次のようなエラーが発生しました。

error: The following untracked working tree files would be overwrittenby merge:     
 Library/Formula/argp-standalone.rb
 Library/Formula/cocot.rb 
Please move or remove them before you can merge. 
Aborting 
Updating e088818..5909e2c 
Error: Failed while executing git pull  origin refs/heads/master:refs/remotes/origin/master

Mountain Lionをインストールした後（私も今週インストールしました）、同じような問題を経験した人のブログ記事を発見しました。彼は、エラーメッセージで言及されているファイルをどのように削除したかを説明しています。

I removed these files:
$ cd $(brew --prefix)
$ rm cocot.rb
However, removing these files didn't help with the brew update. Instead I had to manually update brew through git:
$ cd $(brew --prefix)
$ git fetch origin
$ git reset --hard origin/master
$ brew update
Already up-to-date.

この指示が正しいと仮定して（仮定してはいけないかもしれませんが）、私はこの指示に従い、次のことをやってみました。

    $ cd $(brew --prefix)
    $ rm cocot.rb

しかし、cocot.rbをrmしようとすると、「ファイルが存在しない」と言われてしまいます。

ひとつだけわからないのは cd $(brew --prefix) cdは成功したので、正しいのだと思います -- /usr/localに移動しましたが、削除するファイルはありませんでした。usr/localの中身は

Cellar              clamXav             git             mysql               var Library             doc             heroku              mysql-5.5.15-osx10.6-x86_64 README.md           etc             include             rvm bin             foreman             lib             share

とりあえず、「brew update」を修正する方法をご存知でしょうか？

更新：favorettiさんの指示に従いファイルを削除し、試した結果 chown -R <your_username> $(brew --prefix)/.git を実行すると、次のようなエラーが発生しました。 brew update

error: The following untracked working tree files would be overwritten by merge:
    Library/Aliases/gperftools
    Library/Aliases/hashdeep
    Library/Aliases/htop
    Library/Aliases/nodejs
    Library/Aliases/ocio
    Library/Aliases/oiio
    Library/Aliases/pgrep
    Library/Aliases/pkill
    Library/Aliases/qt4
    Library/Aliases/twolame
    Library/Aliases/wxwidgets
    Library/Contributions/cmds/brew-aspell-dictionaries
    Library/Contributions/cmds/brew-beer.rb
    Library/Contributions/cmds/brew-dirty.rb
    Library/Contributions/cmds/brew-graph
    Library/Contributions/cmds/brew-grep
    Library/Contributions/cmds/brew-leaves.rb
    Library/Contributions/cmds/brew-linkapps.rb
    Library/Contributions/cmds/brew-ls-taps.rb
    Library/Contributions/cmds/brew-man
    Library/Contributions/cmds/brew-md5-to-sha1
    Library/Contributions/cmds/brew-mirror-check.rb
    Library/Contributions/cmds/brew-pull.rb
    Library/Contributions/cmds/brew-readall.rb
    Library/Contributions/cmds/brew-server
    Library/Contributions/cmds/brew-services.rb
    Library/Contributions/cmds/brew-switch.rb
    Library/Contributions/cmds/brew-test-bot.rb
    Library/Contributions/cmds/brew-tests.rb
    Library/Contributions/cmds/brew-unpack.rb
    Library/Contributions/cmds/brew-which.rb
    Library/Contributions/cmds/git
    Library/Contributions/cmds/svn
    Library/ENV/4.3/apr-1-config
    Library/ENV/4.3/bsdmake
    Library/ENV/4.3/c++
    Library/ENV/4.3/c89
    Library/ENV/4.3/c99
    Library/ENV/4.3/cc
    Library/ENV/4.3/clang
    Library/ENV/4.3/clang++
    Library/ENV/4.3/cpp
    Library/ENV/4.3/g++
    Library/ENV/4.3/gcc
    Library/ENV/4.3/git
    Library/ENV/4.3/i686-apple-darwin11-llvm-g++-4.2
    Library/ENV/4.3/i686-apple-darwin11-llvm-gcc-4.2
    Library/ENV/4.3/ld
    Library/ENV/4.3/llvm-g++
    Library/ENV/4.3/llvm-g++-4.2
    Library/ENV/4.3/llvm-gcc
    Library/ENV/4.3/llvm-gcc-4.2
    Library/ENV/4.3/make
    Library/ENV/4.3/mig
    Library/ENV/4.3/sed
    Library/ENV/4.3/svn
    Library/ENV/4.3/xcrun
    Library/ENV/libsuperenv.rb
    Library/ENV/pkgconfig/leopard/libcrypto.pc
    Library/ENV/pkgconfig/leopard/libcurl.pc
    Library/ENV/pkgconfig/mountain_lion/libcurl.pc
    Library/ENV/pkgconfig/mountain_lion/libexslt.pc
    Library/ENV/pkgconfig/mountain_lion/libxml-2.0.pc
    Library/ENV/pkgconfig/mountain_lion/libxslt.pc
    Library/Formula/abcl.rb
    Library/Formula/abcmidi.rb
    Library/Formula/aiccu.rb
    Library/Formula/akka.rb
    Library/Formula/alac.rb
    Library/Formula/alure.rb
    Library/Formula/appledoc.rb
    Library/Formula/arangodb.rb
    Library/Formula/argp-standalone.rb
    Library/Formula/argtable.rb
    Library/Formula/autopano-sift-c.rb
    Library/Formula/avian.rb
    Library/Formula/avidemux.rb
    Library/Formula/avro-cpp.rb
    Library/Formula/aws-cloudsearch.rb
    Library/Formula/aws-sns-cli.rb
    Library/Formula/backupninja.rb
    Library/Formula/bact.rb
    Library/Formula/bam.rb
    Library/Formula/basex.rb
    Library/Formula/berkeley-db4.rb
    Library/Formula/bind.rb
    Library/Formula/blazeblogger.rb
    Library/Formula/bochs.rb
    Library/Formula/boost149.rb
    Library/Formula/bsdconv.rb
    Library/Formula/bsdmake.rb
    Library/Formula/buildapp.rb
    Library/Formula/bup.rb
    Library/Formula/byacc.rb
    Library/Formula/cadubi.rb
    Library/Formula/camellia.rb
    Library/Formula/casperjs.rb
    Library/Formula/ccextractor.rb
    Library/Formula/cconv.rb
    Library/Formula/cdo.rb
    Library/Formula/cdpr.rb
    Library/Formula/cgvg.rb
    Library/Formula/checkstyle.rb
    Library/Formula/chordii.rb
    Library/Formula/chruby.rb
    Library/Formula/cifer.rb
    Library/Formula/clhep.rb
    Library/Formula/cntlm.rb
    Library/Formula/cocot.rb
    Library/Formula/cogl.rb
    Library/Formula/collada-dom.rb
    Library/Formula/crash.rb
    Library/Formula/crossroads.rb
    Library/Formula/crosstool-ng.rb
    Library/Formula/css-crush.rb
    Library/Formula/csync.rb
    Library/Formula/ctemplate.rb
    Library/Formula/curlftpfs.rb
    Library/Formula/cutter.rb
    Library/Formula/cvsutils.rb
    Library/Formula/darkstat.rb
    Library/Formula/darner.rb
    Library/Formula/dart.rb
    Library/Formula/dasm.rb
    Library/Formula/debianutils.rb
    Library/Formula/dfc.rb
    Library/Formula/dgtal.rb
    Library/Formula/dhcping.rb
    Library/Formula/di.rb
    Library/Formula/dmtx-utils.rb
    Library/Formula/drip.rb
    Library/Formula/dsniff.rb
    Library/Fo
Aborting
Updating e088818..c1fbc29
Error: Failed while executing git pull  origin refs/heads/master:refs/remotes/origin/master

解決方法は？

cd $(brew --prefix)
git reset --hard HEAD
brew update