COOK-2750 enable passenger apache module in mod_rails recipe

Some users just put mod_rails recipe in their run_list instead of
the default recipe since that worked prior to the 2.0 release of
this cookbook.
This ensures the passenger apache module files are created before
attempting to enable the module.
Merge pull request #15 from opscode-cookbooks/jhs/COOK-2750

COOK-2750 enable passenger apache module in mod_rails recipe