Update cirros version
Update cirros version

This now matches the version that is included in DevStack.

Change-Id: I41eafc754bb2a3591e7352ee817dce3aff992db2
Closes-Bug: #1453357

maestro-hybrid-cloud/heat,rh-s/heat,dims/heat,pratikmallya/heat,dragorosson/heat,takeshineshiro/heat,takeshineshiro/heat,cwolferh/heat-scratch,pratikmallya/heat,cwolferh/heat-scratch,gonzolino/heat,miguelgrinberg/heat,gonzolino/heat,jasondunsmore/heat,steveb/heat,steveb/heat,cryptickp/heat,rdo-management/heat,noironetworks/heat,maestro-hybrid-cloud/heat,rh-s/heat,srznew/heat,openstack/heat,cryptickp/heat,rdo-management/heat,noironetworks/heat,srznew/heat,pshchelo/heat,dragorosson/heat,openstack/heat,dims/heat,pshchelo/heat,miguelgrinberg/heat,jasondunsmore/heat