Support platforms without quantum server package

RedHat platforms don't have a separate package for the quantum server.

Change-Id: Ied83733f1dc8ec55a664e1d9c7119d3105a0a8e2
Support platforms without ovs agent package

RedHat platforms don't have a separate package for the ovs agent.

Change-Id: Ib782dd38af3dd37c2f0921479eeffd93b2f46cb1
Support platforms without dhcp agent package

RedHat platforms don't have a separate package for the dhcp agent.

Change-Id: Ie336499c3d86b358f609cb9c49d748f4b522f0df