disk.c: added kludge against premature failure

This hardcoded pause is ugly indeed but forcing users
into wondering what goes on behind bootsplash *sometimes*
(depending on usbflash controller type *and* state) is worse.

Any ideas on reliably fixing this are welcome, of course.

See also http://bugzilla.altlinux.org/30315

disk.c

@@ -359,6 +359,13 @@ enum return_type disk_prepare(void)
 		return RETURN_BACK;
 	}
 
+	if (try_with_uuidlabel() == RETURN_OK)
+		return RETURN_OK;
+
+	/* let's try this again after having waited a bit for
+	 * some slower/more sophisticated controllers to init */
+	spawn(udevtrigger_add);
+	sleep(2);
 	if (try_with_uuidlabel() == RETURN_OK)
 		return RETURN_OK;