reboot: Wait a bit on successful signal delivery

To prevent returning the prompt too soon, and thereby messing up the
output from Finit, wait a bit after successful delivery of signal to
reboot/halt/poweroff.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

reboot.c

@@ -191,6 +191,8 @@ int main(int argc, char *argv[])
 
 	if (c)
 		err(1, "Failed signalling init to %s", msg);
+	else
+		sleep(2);
 
 	return 0;
 }