Move gerrit replication waiting queue aside during project renames

We will be doing our first set of project renames in about a month since
we've noticed that the waiting queue is not draining properly. The
contents of this queue produce many scary looking (on the order of
thousands) exceptions during gerrit startup. Move the queue aside to
avoid confusion and uncertainty of problems during the project rename
process.

Change-Id: I3cd8fd17de340d536dd7e4e07fa1e18c86107832

playbooks/rename_repos.yaml

@@ -86,6 +86,22 @@
     - name: Make backup of gerrit index
       shell: cp -ax /home/gerrit2/review_site/index /home/gerrit2/index.backup.$(date +%s)
 
+    # As an alternative we can simply delete the waiting queue. Previously
+    # these were copied for debugging purposes but the problems are
+    # reasonably well understood so we probably don't need to keep collecting
+    # more data.
+    # We use the tmp/ path because it is not backed up and we don't need to
+    # preserve this information long term.
+    - name: Create replication queue target location
+      file:
+        path: /home/gerrit2/tmp/replication_waiting_queues
+        state: directory
+        mode: '0755'
+        owner: gerrit2
+        group: gerrit2
+    - name: Move the replication plugin waiting queue aside due to bugs
+      shell: mv /home/gerrit2/review_site/data/replication/ref-updates/waiting /home/gerrit2/tmp/replication_waiting_queues/waiting_queue_$(date +%s)
+
 - hosts: review
   gather_facts: False
   remote_user: root