"publicurl" should be required on endpoint-create

publicurl field is required and cannot be empty when create a endpoint in
keystone server.So the "--publicurl " also should set as mandatory in
keystoneclient.

Change-Id: Ia397c79a28dd3a6ddef141df0f7df30cc0bf7b6c
Closes-Bug: #1246335
Merge ""publicurl" should be required on endpoint-create"