Add memcached_servers so that nova-consoleauth can share tokens properly

add memcached_servers into the same location as in upstream puppet-nova.
Also updated openstack::compute to use same code path

Change-Id: I5f94322bb74dd52fcfd3f923a6583bd742618849
Closes-bug: #1323705
Merge "Add memcached_servers so that nova-consoleauth can share tokens properly"