Bug 1332217: Set default security group if not specified during port_create
Bug 1332374: Do not reset security_group_list unconditionally. Only reset if new list is specified in the request

Change-Id: Id011131dee379ba0d6481406e8e967c1d9d1f965
Merge "Bug 1332217: Set default security group if not specified during port_create Bug 1332374: Do not reset security_group_list unconditionally. Only reset if new list is specified in the request"