Fix missing/incorrect yum packages

Sources:
- http://docs.openstack.org/folsom/openstack-compute/install/yum/content/installing-openstack-dashboard.html#comment-755806711
- http://docs.openstack.org/folsom/openstack-compute/install/yum/content/installing-openstack-dashboard.html#comment-843089682

Change-Id: Ib7d77ea7c25ab74123c612fd116d63fac7b92ac0