title: Brew Update not working after mac 10.9
body: <p>First time running brew since 10.9 upgrade. </p>
  
  <p>From the output below, should I just remove Library/Formula/ant.rb and Library/Formula/apple-gcc42.rb? Also, unclear why git pull is failing. Thanks for any help</p>
  
  <pre><code>525    [projects]$  brew --config
  HOMEBREW_VERSION: 0.9.4
  ORIGIN: https://github.com/mxcl/homebrew.git
  HEAD: 27c26faf7b958de6028ad55be8ccc5a57b094d3f
  HOMEBREW_PREFIX: /usr/local
  HOMEBREW_CELLAR: /usr/local/Cellar
  CPU: 8-core 64-bit ivybridge
  OS X: 10.9-x86_64
  Xcode: 5.0.2
  GCC-4.2: build 5666
  LLVM-GCC: build 0
  Clang: 5.0 build 500
  X11: N/A
  System Ruby: 1.8.7-358
  Perl: /usr/bin/perl
  Python: /usr/bin/python
  Ruby: /Users/*****/.rvm/rubies/ruby-2.0.0-p195/bin/ruby
  526    [projects]$  brew update
  error: The following untracked working tree files would be overwritten by merge:
      Library/Formula/ant.rb
      Library/Formula/apple-gcc42.rb
  Please move or remove them before you can merge.
  Aborting
  Error: Failure while executing: git pull -q origin refs/heads/master:refs/remotes/origin/master
  </code></pre>