Merge pull request benoitc#2785 from mvdbeek/make_loggers_function_atomic

Make loggers function atomic

Author: benoitc

gunicorn/glogging.py

@@ -90,7 +90,7 @@
 def loggers():
  """ get list of all loggers """
  root = logging.root
- existing = root.manager.loggerDict.keys()
+ existing = list(root.manager.loggerDict.keys())
  return [logging.getLogger(name) for name in existing]