Add ansible_python_interpreter to Ceph playbook
Add ansible_python_interpreter to Ceph playbook

CentOS deploys of Ceph will fail due to missing libpython-selinux
package, even though it is installed. We need to ensure the correct
python_interpreter is used to ensure this failure doesn't occur.

Change-Id: Icaee6367081656dfa976ce7b83885eb59dbe3416

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