tree-wide: do not print hint about -M if -M is already used

(Or when -H is used, since -H and -M are incompatible.)

Note that the slightly unusual form with separate boolean variables (hint_vars,
hint_addr) instead of e.g. a const char* variable to hold the message, because this
way we don't trigger the warning about non-literal format.

src/run/run.c

@@ -1760,7 +1760,7 @@ static int run(int argc, char* argv[]) {
         else
                 r = bus_connect_transport_systemd(arg_transport, arg_host, arg_user, &bus);
         if (r < 0)
-                return bus_log_connect_error(r);
+                return bus_log_connect_error(r, arg_transport);
 
         if (arg_scope)
                 r = start_transient_scope(bus);