ecore_wl2: Fix session recovery

I broke this in commit 1bb45f6e61

We intentionally *don't* flush in window_semi_free, as this could be
when there's no compositor left to flush to (in the case of session
recovery).

src/lib/ecore_wl2/ecore_wl2_window.c

@@ -24,7 +24,6 @@ _ecore_wl2_window_semi_free(Ecore_Wl2_Window *window)
    if (window->surface) wl_surface_destroy(window->surface);
    window->surface = NULL;
    window->surface_id = -1;
-   ecore_wl2_display_flush(window->display);
 }