prevent packstack from aborting of o-p-m package has no deps

If the openstack-puppet-modules has no dependencies (other than those
explicitly filtered out), packstack will abort with an error.  This
patch allows the deployment to continue even if the egrep filter returns
an error.

Change-Id: I5642717d2dc093a18e6d1b0dc7f6f782426db843
Closes-bug: #1332705
Merge "prevent packstack from aborting of o-p-m package has no deps"