Remove trailing commas in contrib roles

The latest omnibus chef mistakenly uses a system level ruby for the
cookbook syntax checks instead of itself. If you are on a system that
has Ruby 1.8.7 installed, the syntax chef will fail for uploads for
things the older Ruby doesn't understand, like trailing commas, newer
hash syntax, etc.

See also http://tickets.opscode.com/browse/CHEF-4460
Merge pull request #25 from claco/fix-commas-chef-4460

Merged automatically by jenkins after successful build test