compositor-x11: use _checked() with xkb_select_events to test for error

In order to use xcb_request_check(), given a request without a reply,
you need to use the _checked() variant of the request function.
See xcb-requests(3).

Signed-off-by: Ran Benita <ran234@gmail.com>

src/compositor-x11.c

@@ -206,7 +206,7 @@ x11_compositor_setup_xkb(struct x11_compositor *c)
 	}
 	c->xkb_event_base = ext->first_event;
 
-	select = xcb_xkb_select_events(c->conn,
+	select = xcb_xkb_select_events_checked(c->conn,
 					       XCB_XKB_ID_USE_CORE_KBD,
 					       XCB_XKB_EVENT_TYPE_STATE_NOTIFY,
 					       0,