Fix error checking in wxFileSystemWatcher::Remove() under OS X.

The boolean return value was compared with -1 which was always false.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74518 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/fswatcher_kqueue.cpp

@@ -149,8 +149,7 @@ public:
         // TODO more error conditions according to man
         // XXX closing file descriptor removes the watch. The logic resides in
         // the watch which is not nice, but effective and simple
-        bool ret = watch->Close();
-        if (ret == -1)
+        if ( !watch->Close() )
         {
             wxLogSysError(_("Unable to remove kqueue watch"));
             return false;