Bug fix for METAFILES that are actually directories.

If a package contains a folder that has the same name as one of our
expected meta files, skip trying to install that folder.

(Otherwise we install an empty folder and can get odd permission errors
when trying to summarize after install.)

Library/Homebrew/install.rb

@@ -96,6 +96,7 @@ def install f
         beginning=Time.now
         f.install
         FORMULA_META_FILES.each do |file|
+          next if File.directory? file
           FileUtils.mv "#{file}.txt", file rescue nil
           f.prefix.install file rescue nil
           (f.prefix+file).chmod 0644 rescue nil