keystone: fix prefixed URL
keystone: fix prefixed URL

Commit 2ad1a42ca667ff21e6f7d2ae906be23a20430036 broke entirely the
Apache configuration for Keystone when used without a port on the
/identity URL. This patch fixes that.

Change-Id: I47805138c66456c9c5fa9af1f4ac33b03d0ce5b9

samgoon/devstack,prithivm/branch01,group-policy/devstack,dtroyer/devstack,dtroyer/devstack,richliu/devstack,noironetworks/devstack,openstack-dev/devstack,bigswitch/devstack,dirkmueller/devstack,thomasem/devstack,Mahito/devstack,mssumanth/devstack,dirkmueller/devstack,Mahito/devstack,group-policy/devstack,samgoon/devstack,richliu/devstack,varunarya10/devstack,mssumanth/devstack,bswartz/devstack,avvocatodemarchis/devstack,varunarya10/devstack,bswartz/devstack,prithivm/branch01,nawawi/openstack,thomasem/devstack,bigswitch/devstack,openstack-dev/devstack,avvocatodemarchis/devstack,noironetworks/devstack,nawawi/openstack