MINOR: listener: move the INHERITED flag down to the receiver

It's the receiver's FD that's inherited from the parent process, not
the listener's so the flag must move to the receiver so that appropriate
actions can be taken.
diff --git a/src/mworker.c b/src/mworker.c
index 1caec10..d6365e1 100644
--- a/src/mworker.c
+++ b/src/mworker.c
@@ -426,7 +426,7 @@
 				/* unbind the listener but does not close if
 				   the FD is inherited with fd@ from the parent
 				   process */
-				if (l->options & LI_O_INHERITED)
+				if (l->rx.flags & RX_F_INHERITED)
 					unbind_listener_no_close(l);
 				else
 					unbind_listener(l);