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/machine/machinectl.c

@@ -2869,7 +2869,7 @@ static int run(int argc, char *argv[]) {
 
         r = bus_connect_transport(arg_transport, arg_host, false, &bus);
         if (r < 0)
-                return bus_log_connect_error(r);
+                return bus_log_connect_error(r, arg_transport);
 
         (void) sd_bus_set_allow_interactive_authorization(bus, arg_ask_password);