Fix neutron V2 No valid authentication is available problem
Fix neutron V2 No valid authentication is available problem

neutron v2 client need admin context, or it will cause the failure

Change-Id: I3a7d1eee60dd513756755f1da29c131e543cebb0
Closes-Bug: #1469625

stackforge/powervc-driver,openstack/powervc-driver,openstack/powervc-driver,stackforge/powervc-driver