cut & paste gone wrong: use the correct field name for the old wnd pr…

…oc..

git-svn-id: https://xpra.org/svn/Xpra/trunk@8713 3bb7dfac-3a0b-4e04-842a-767bc560f471

src/xpra/platform/win32/window_hooks.py

@@ -74,11 +74,11 @@ def cleanup(self, *args):
         log("cleanup%s", args)
         self._message_map = {}
         #since we assume the window is closed, restoring the wnd proc may be redundant here:
-        if not self.old_win32_proc or not self._hwnd:
+        if not self._oldwndproc or not self._hwnd:
             return
         try:
             win32api.SetWindowLong(self._hwnd, win32con.GWL_WNDPROC, self._oldwndproc)
-            self.old_win32_proc = None
+            self._oldwndproc = None
             self._hwnd = None
         except:
             log.error("cleanup", exc_info=True)