Add keystone middleware to devstack

Add the keystonemiddleware repository to devstack to support testing
with tempest and stable branches.

Change-Id: Ib635465e6568d9cd51d6e432ec8b8633a27d19ce
fix trove image addition

the previous addition to trove was done in a way that it was not
possible to discover from nodepool. This fixes our ability to do
that, especially with non-default on services.

Change-Id: I8ca682354e0d4e2eb9cf05f40c6dd783de1c6355
Merge "Add keystone middleware to devstack"
Merge "fix trove image addition"
Merge branch 'master' of https://github.com/openstack-dev/devstack