missing module added

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@35521 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gui_modules/mapdisp_window.py

@@ -20,6 +20,7 @@ for details.
 import os
 import time
 import math
+import sys
 
 import wx