Python 3 preparation: avoid logging._levelNames.

logging._levelNames is an internal name, not a public interface, and
is not available in current Python 3.  Fortunately, logger.setLevel
accepts strings for log levels, not just numeric levels, in 2.7
(although that change is not mentioned in the 2.7 documentation).

Author: jsm28

roundup/configuration.py

@@ -1625,7 +1625,7 @@ def init_logging(self):
             h.close()
             logger.removeHandler(hdlr)
         logger.handlers = [hdlr]
-        logger.setLevel(logging._levelNames[self["LOGGING_LEVEL"] or "ERROR"])
+        logger.setLevel(self["LOGGING_LEVEL"] or "ERROR")
 
     def load(self, home_dir):
         """Load configuration from path designated by home_dir argument"""