Ensures a api requests is done for glance-image-exists
Ensures a api requests is done for glance-image-exists

Closes-bug: #47

stackforge/monitoring-for-openstack,padthaitofuhot/monitoring-for-openstack,tcpcloud/monitoring-for-openstack,tcpcloud/monitoring-for-openstack,magic0704/monitoring-for-openstack,magic0704/monitoring-for-openstack,openstack/monitoring-for-openstack,stackforge/monitoring-for-openstack,openstack/monitoring-for-openstack,padthaitofuhot/monitoring-for-openstack