Fixed missing NullHanlder in Python 2.6

Author: expobrain

git/util.py

@@ -41,6 +41,14 @@
 )
 from .exc import InvalidGitRepositoryError
 
+
+if not hasattr(logging, 'NullHandler'):
+    class NullHandler(logging.Handler):
+        def emit(self, record):
+            pass
+
+    logging.NullHandler = NullHandler
+
 log = logging.getLogger('git.util')
 log.addHandler(logging.NullHandler())