Check nova VM status in CI

Previously we were not checking the status of created VMs in CI, meaning
that VM creation failures would be silently ignored. This change checks
the status, requiring it to be ACTIVE for a pass.

Change-Id: Ia559c81b4944c2c6c7dedfca0c6c570db390704b

dev/functions

@@ -231,6 +231,11 @@ function overcloud_test {
     echo "Creating a VM"
     openstack server create --wait --image cirros --flavor m1.tiny --key-name mykey --network demo-net demo1
     openstack server show demo1
+    status=$(openstack server show demo1 -f value -c status)
+    if [[ $status != ACTIVE ]]; then
+        echo "VM creation failed"
+        return 1
+    fi
     # TODO(mgoddard): Test SSH connectivity to the VM.
 
     echo "Deleting the VM"