doc: Update project port create
doc: Update project port create

Non admin users can create a port now.
This commit updates the corresponding document.

Change-Id: Iaa5678f70c4f67d6255448ed3dd0fe4e7d67a27a

openstack/horizon,openstack/horizon,openstack/horizon,noironetworks/horizon,ChameleonCloud/horizon,ChameleonCloud/horizon,NeCTAR-RC/horizon,noironetworks/horizon,noironetworks/horizon,NeCTAR-RC/horizon,openstack/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,NeCTAR-RC/horizon,ChameleonCloud/horizon,noironetworks/horizon