wxGUI/nviz: os module added (merge from devbr6, https://trac.osgeo.org/grass/changeset/32870)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32871 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/gui_modules/nviz.py

@@ -19,6 +19,7 @@ for details.
 
 errorMsg = ''
 
+import os
 import sys
 
 import wx