Comment 4 for bug 1180670

Just happend on the gate at http://logs.openstack.org/12/52312/1/check/gate-nova-python27/571e82b/console.html

A quick search with logstash confirms that this has started to happen frequently over the last couple of days.
Logstash query: @message:"FAIL: nova.tests.virt.xenapi.test_xenapi.XenAPIVMTestCase.test_instance_snapshot_fails_with_no_primary_vdi"