Added retries for db_sync

If db sync fails, it is never retried leading to errors. So, this
patch adds retries for db_sync to avoid sync fails.

Change-Id: I64e011820591796168cafa4e0a93d5e2157ce445
Closes-Bug: #1628580

manifests/db/sync.pp

@@ -13,6 +13,8 @@ class manila::db::sync {
     path        => '/usr/bin',
     user        => 'manila',
     refreshonly => true,
+    try_sleep   => 5,
+    tries       => 10,
     logoutput   => 'on_failure',
   }
 }