Fix Mountain Lion sed by setting LANG.

It's also necessary to delete LC_ALL or it overrides the new LANG.
LC_COLLATE is the problem variable but is affected by LANG and LC_ALL
so just use them instead. Extends the fix made to geoip in dc955c.

Fix Homebrew/homebrew#11728, fix Homebrew/homebrew#12890, fix Homebrew/homebrew#13653, fix Homebrew/homebrew#13734, fix Homebrew/homebrew#13787, fix Homebrew/homebrew#13818.

Formula/geoip.rb

@@ -14,8 +14,6 @@ class Geoip < Formula
   end
 
   def install
-    # Fix issue with sed barfing on unicode characters on Mountain Lion.
-    ENV.delete('LANG')
     ENV.universal_binary if ARGV.build_universal?
 
     # Fixes a build error on Lion when configure does a variant of autoreconf