Fix bug in verbose() (need variable's value, not its name)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@34282 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/grass.py

@@ -358,7 +358,7 @@ def overwrite():
 
 def verbosity():
     """Return the verbosity level selected by GRASS_VERBOSE"""
-    vbstr = 'GRASS_VERBOSE'
+    vbstr = os.getenv('GRASS_VERBOSE')
     if vbstr:
 	return int(vbstr)
     else: