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/proxy.c b/src/proxy.c
index 3f25dac..21d11ee 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -1370,7 +1370,7 @@
 			continue;
 		}
 		/* The master should not close an inherited FD */
-		if (master && (l->options & LI_O_INHERITED))
+		if (master && (l->rx.flags & RX_F_INHERITED))
 			unbind_listener_no_close(l);
 		else
 			unbind_listener(l);