cleaner: remove lib/charset.alias files

This file is installed by a number of packages, but it really shouldn't
be. It is meant to be updated by packages that use it, but this is
broken (1) by software that doesn't do this correctly and (2) by the
symlink being overwritten by Homebrew's linking code.

It's presence can cause issues with tools that use libiconv/gettext.

Instead let's follow MacPorts' example and just remove it during the
clean stage.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Library/Homebrew/cleaner.rb

@@ -78,6 +78,8 @@ class Cleaner
       elsif path.extname == '.la'
         # *.la files are stupid
         path.unlink unless @f.skip_clean? path
+      elsif path == @f.lib+'charset.alias'
+        path.unlink unless @f.skip_clean? path
       elsif not path.symlink?
         clean_file path
       end