window: Erase wrong comment and workaround

The commit[0] which introduced this comment aimed to fix a bug which was
caused by double-clicking a folder on the view.[1]

This change was ineffective as per later comments on that bug report,
which is not surprising because the change was wrong: this code path was
(and still is) used only for changing locations using the pathbar and
sidebar. The bug happening with double-click on the view is uses another
code path, in mime-actions.c, which has later been patched[2].

So, let's remove the wrong FIXME comment and effectively revert [0],
which, as expected, doesn't introduce any bug in my testing.

[0] 49c03251ee
[1] https://bugzilla.gnome.org/show_bug.cgi?id=756499
[2] 755c771058

src/nautilus-window.c

@@ -682,11 +682,8 @@ open_location_cb (NautilusWindow    *window,
     }
 
     application = NAUTILUS_APPLICATION (g_application_get_default ());
-    /* FIXME: We shouldn't need to provide the window, but seems gtk_application_get_active_window
-     * is not working properly in GtkApplication, so we cannot rely on that...
-     */
     nautilus_application_open_location_full (application, location, flags,
-                                             NULL, window, NULL);
+                                             NULL, NULL, NULL);
 
     if (adw_overlay_split_view_get_collapsed (split_view) &&
         flags == NAUTILUS_OPEN_FLAG_NORMAL)