Project updates must run on controller nodes

For project updates jobs triggered due a job template run,
we must ensure that project_update job to run on at the same
controller which dispatched the original job template, otherwise
the job might fail for being unable to find the playbook YAML file.

awx/main/tasks.py

@@ -1865,7 +1865,7 @@ class RunJob(BaseTask):
 
         if sync_needs:
             pu_ig = job.instance_group
-            pu_en = job.execution_node
+            pu_en = Instance.objects.me().hostname
 
             sync_metafields = dict(
                 launch_type="sync",