Have ansible retry ssh connections

In zuul's ansible config we add retries=3 to deal with transient issues.
Do the same thing for our production runs.

Change-Id: Ide53bae34e5e622de1fd4741706752e8728da20e

playbooks/roles/install-ansible/files/ansible.cfg

@@ -19,4 +19,5 @@ cache_plugin=jsonfile
 cache_connection=/var/cache/ansible/inventory
 
 [ssh_connection]
+retries=3
 pipelining = True