Fix set_ovs_hostconfigs exit issue
Fix set_ovs_hostconfigs exit issue

When Open_vSwitch has no datapath_types available in the
database that causes set_ovs_hostconfigs to fail.

Change-Id: I8f95801f49b7463f25391c213e673a419a725bd0

openstack/networking-odl,openstack/networking-odl,openstack/networking-odl