In a failover situation get the nodes in a well defined order.

When deciding which node will be the new master, we should get the
nodes in a well defined order otherwise two standbys could process
nodes with the same priority in different order and end up with
a two master situation.

repmgrd.c

@@ -625,7 +625,7 @@ do_failover(void)
 	        "  FROM %s.repl_nodes "
 	        " WHERE id <> %d "
 	        "   AND cluster = '%s' "
-	        " ORDER BY priority ",
+	        " ORDER BY priority, id ",
 	        repmgr_schema, primary_options.node, local_options.cluster_name);
 
 	res1 = PQexec(myLocalConn, sqlquery);