Related-Bug: #1390392
Temporary fix to have stable build as some of commits didn't get through
Zuul

Change-Id: Ic63a60174e913955110d09051f101ece52fb9263
Related-Bug: #1390392

Disable Add/Delete IPAM in Configure > Networking > IPAM page in case of vCenter
Hide "Add Subnet button" in Create Network dialog in case of vCenter

Change-Id: I92c669f50653f743a130760572a87b7957ca68c9