Fix RGW endpoint port

Change RGW endpoint port registered in keystone
to 8080 as this is the real port on which
haproxy is listening.

Previously, until https://review.openstack.org/#/c/85195/
was merged, RGW was working because virtual IP was located
on one of the controllers and apache proxying RGW fastcgi
application was answering on 6780 port. Currently, VIP moved
into namespace and 6780 is no longer available.

Change-Id: Ib5c20760af7c20a5b2b45fcc899cdc113845ea3f
Closes-Bug: #1307508