Improve pg_upgrade wording for pg_ctl start failure; could be

connection failure.

Backpatch to 9.2.

Per report from Evan D. Hoffman

contrib/pg_upgrade/server.c

@@ -193,7 +193,7 @@ start_postmaster(ClusterInfo *cluster)
 
 	/* If the connection didn't fail, fail now */
 	if (pg_ctl_return != 0)
-		pg_log(PG_FATAL, "pg_ctl failed to start the %s server\n",
+		pg_log(PG_FATAL, "pg_ctl failed to start the %s server, or connection failed\n",
 			   CLUSTER_NAME(cluster));
 
 	os_info.running_cluster = cluster;