wxGUI: globalvar.GetGRASSCmd() returns `set`

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@49919 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/core/globalvar.py

@@ -181,7 +181,7 @@ def GetGRASSCmds(scriptsOnly = False):
                 else:
                     cmd.append(fname)
     
-    return cmd
+    return set(cmd)
 
 """@brief Collected GRASS-relared binaries/scripts"""
 grassCmd = {}