nolabs: Use new version of engine

Change-Id: I2e9c70dc8a5c6331ebb0c4128848ea29f45c1cdf
diff --git a/jjb/nolabs/nolabs-booking-jobs.yaml b/jjb/nolabs/nolabs-booking-jobs.yaml
index accdf39..f367969 100644
--- a/jjb/nolabs/nolabs-booking-jobs.yaml
+++ b/jjb/nolabs/nolabs-booking-jobs.yaml
@@ -125,7 +125,7 @@
           description: 'Python virtualenv location to use.'
       - string:
           name: GERRIT_REFSPEC
-          default: 'refs/changes/79/2079/10'
+          default: 'refs/changes/74/3574/3'
           description: 'Refspec to checkout'
       - string:
           name: HEAT_ENVIRONMENT_FILE