Default app status to REGISTERED
Default app status to REGISTERED

If an app is new or simply owns no assemblies, display a status
of REGISTERED instead of an empty list. This also helps convey
that creating (registering) an app does not immediately invoke
the test/build/deploy process.

Closes-Bug: #1430522

Change-Id: I24aa0170a0228ed6e097203edb3cb76101745260

stackforge/python-solumclient,openstack/python-solumclient,stackforge/python-solumclient