pygrass: Add unicode variable to support python3

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@65594 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/pygrass/modules/interface/module.py

@@ -20,6 +20,7 @@ if sys.version_info[0] == 2:
     from itertools import izip_longest as zip_longest
 else:
     from itertools import zip_longest
+    unicode = str
 
 
 def _get_bash(self, *args, **kargs):