catch NullHandler error for py2.6

pyotrs/__init__.py

@@ -15,5 +15,11 @@ from .lib import Ticket  # noqa
 
 # Set default logging handler to avoid "No handler found" warnings.
 import logging
-from logging import NullHandler  # Python 2.7+  (Python 2.6 is **not** supported)
+try:  # Python 2.7+
+    from logging import NullHandler
+except ImportError:
+    class NullHandler(logging.Handler):
+        def emit(self, record):
+            pass
+
 logging.getLogger(__name__).addHandler(NullHandler())