parasite: Print unknown command number

Convenient for debugging
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

pie/parasite.c

@@ -654,6 +654,6 @@ int __used parasite_service(unsigned int cmd, void *args)
 		return parasite_dump_tty(args);
 	}
 
-	pr_err("Unknown command to parasite\n");
+	pr_err("Unknown command to parasite: %d\n", cmd);
 	return -EINVAL;
 }