can't access git on heroku

config/initializers/git_info.rb

@@ -2,6 +2,7 @@
 #   licensed under the Affero General Public License version 3 or later.  See
 #   the COPYRIGHT file.
 
+unless ENV['HEROKU']
   s = `git show --name-only 2>/dev/null || :`
   if (s.nil? or s.empty?)
        path =  File.expand_path("config/gitversion")
@@ -21,3 +22,6 @@ end
   GIT_INFO = s
   # What's the scope of this s? Leave to GC just in case...
   s = nil
+else
+  GIT_INFO = nil
+end