Puppet Support

To reproduce:

1. Follow the xinetd module builder
2. Edit the PULP_MANIFEST to copy the first line to the second line
3. Run the following Pulp commands:

pulp-admin login -u admin -p admin
pulp-admin puppet repo create --repo-id=acme --feed=file:///opt/puppet/modules/
pulp-admin puppet repo sync run --repo-id acme

You'll see this traceback in the logs and the CLI will error:

 Traceback (most recent call last):
   File "/usr/lib/python2.7/site-packages/celery-3.1.11-py2.7.egg/celery/app/trace.py", line 240, in trace_task
     R = retval = fun(*args, **kwargs)
   File "/home/bmbouter/Documents/pulp/server/pulp/server/async/tasks.py", line 393, in __call__ 
     return super(Task, self).__call__(*args, **kwargs)
   File "/usr/lib/python2.7/site-packages/celery-3.1.11-py2.7.egg/celery/app/trace.py", line 437, in __protected_call__
     return self.run(*args, **kwargs)
   File "/home/bmbouter/Documents/pulp/server/pulp/server/controllers/repository.py", line 555, in sync
     sync_report = sync_repo(transfer_repo, conduit, call_config)
   File "/home/bmbouter/Documents/pulp/server/pulp/server/async/tasks.py", line 558, in wrap_f   
     return f(*args, **kwargs)
   File "/home/bmbouter/Documents/pulp_puppet/pulp_puppet_plugins/pulp_puppet/plugins/importers/importer.py", line 65, in sync_repo
     report = self.sync_method()
   File "/home/bmbouter/Documents/pulp_puppet/pulp_puppet_plugins/pulp_puppet/plugins/importers/directory.py", line 317, in __call__
     self._import_modules(module_paths)
   File "/home/bmbouter/Documents/pulp_puppet/pulp_puppet_plugins/pulp_puppet/plugins/importers/directory.py", line 265, in _import_modules
     module.save()
   File "/usr/lib/python2.7/site-packages/mongoengine/document.py", line 359, in save
     raise NotUniqueError(message % unicode(err))
 NotUniqueError: Tried to save duplicate unique keys (insertDocument :: caused by :: 11000 E11000 duplicate key error index: pulp_database.units_puppet_module.$name_1_version_1_author_1  dup key: { : "puppetlabs-xinetd", : "1.5.0", : "puppetlabs" })