Ensure keystone endpoint set before service starts

This patch ensures that in the case where keystone and
glance-api are on the same node, nova-api is not started
until the keystone catalog contains the image service
and endpoint required to use glance.

Change-Id: I48ae07b2d7789d549a4412a21e842a1222a48caa
Merge git://github.com/puppetlabs/puppetlabs-glance