1146916 - pulp-puppet-module-builder now builds modules without init.pp files

This addresses both of the following bugs: 
 * https://bugzilla.redhat.com/show_bug.cgi?id=1146916
 * https://bugzilla.redhat.com/show_bug.cgi?id=1146834

The tool will now attempt to build a module from any directory containing a `Modulefile` (the old metadata file) or a `metadata.json`. The one exception is if the module is in a `pkg`  directory(e.g. `puppetlabs-mysql/pkg/puppetlabs-mysql/metadata.json`), which is created when `puppet module build puppetlabs-mysql` is run