event: destroy: recheck client instead of unmark client

We detach the client window from its frame when it's destroyed, so later
a new window can be attached to that frame. But turns out that's not
enough.

When i3 restarts, it attaches a placeholder window to the frame, then
the real window, and only after that, it will destroy the placeholder.
The real window will fail to attach as the frame already has a client.
When the placeholder is destroyed, we have to call recheck client to
pick up the real window that failed to attach previously.

Related: #299

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/event.c

@@ -274,7 +274,7 @@ static inline void ev_destroy_notify(session_t *ps, xcb_destroy_notify_event_t *
 	if (w != NULL) {
 		auto _ attr_unused = destroy_win_start(ps, w);
 	} else if (mw != NULL) {
-		win_unmark_client(ps, mw);
+		win_recheck_client(ps, mw);
 	} else {
 		log_debug("Received a destroy notify from an unknown window, %#010x",
 		          ev->window);