Raise on error in get_msgr() function.

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@58951 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/python/pygrass/messages/__init__.py

@@ -317,7 +317,7 @@ class Messenger(object):
         time.sleep(1)
 
 
-def get_msgr(_instance=[None, ]):
+def get_msgr(_instance=[None, ], raise_on_error=False):
     """!Return a Messenger instance.
 
     @return the Messenger instance.
@@ -332,7 +332,7 @@ def get_msgr(_instance=[None, ]):
         False
     """
     if not _instance[0]:
-        _instance[0] = Messenger()
+        _instance[0] = Messenger(raise_on_error)
     return _instance[0]