Switch openstack_version back to 'master'
Switch openstack_version back to 'master'

Change-Id: I30c56ae696ec29db243a25959523b829a6c76600

bunchc/openstack-ansible,openstack/openstack-ansible,stackforge/os-ansible-deployment,openstack/openstack-ansible,bunchc/openstack-ansible,stackforge/os-ansible-deployment