set dhcp_agent_manager for ovs plugin

related to bug 1131446, makes makes this setting no longer the default,
as doing so broke DHCP for other plugins.

Change-Id: I01ff9e00ba8d416179b485000e69cf3b3908b7bf
Added cinder-backup service (not enabled by default)

cinder-backup service has been added to cinder. This fix adds the
cinder-backup service. To enable this service, c-bak must be added
to ENABLED_SERVICES in the users localrc. To actually perform a
backup the user must enable swift or another service.

Change-Id: If4ef8d78081be572987e7c38c76ff57e82b4f744
Merge "set dhcp_agent_manager for ovs plugin"