Add openrc_region_name to define the service region for openrc files.
Add openrc_region_name to define the service region for openrc files.

This allows openstack_openrc to explicitly set the correct region
in openrc and clouds.yaml. openstack_openrc is a dependency of all
os_* roles.

Change-Id: I3f055c87a66e683f459d62a839c03230c43d83b2

yanyao/newton,os-cloud/os-ansible-deployment,cfarquhar/openstack-ansible,robb-romans/openstack-ansible,yanyao/openstack-ansible,weezer/openstack-ansible,openstack/openstack-ansible,openstack/openstack-ansible,bunchc/openstack-ansible,stackforge/os-ansible-deployment,cloudnull/os-ansible-deployment,cloudnull/os-ansible-deployment,BjoernT/os-ansible-deployment,BjoernT/os-ansible-deployment,bunchc/openstack-ansible,Logan2211/openstack-ansible,yanyao/newton,BjoernT/os-ansible-deployment,robb-romans/openstack-ansible,BjoernT/openstack-ansible,cfarquhar/openstack-ansible,Logan2211/openstack-ansible,BjoernT/openstack-ansible,stackforge/os-ansible-deployment,yanyao/openstack-ansible,os-cloud/os-ansible-deployment,weezer/openstack-ansible