User password update hardcoded the endpoint_filter to always use the public
endpoint. This will break deployments where services behind the firewall have
no access to the public endpoint. Endpoint selection should be allowed
by the end user (i.e. openstack --os-interface internal user password set).
Closes-Bug: 1503459
Change-Id: Ib11d60cd8e81b99aedb27f1cbbf6b79218045cf0