Compatibility fix: use isAlive instead of is_alive for python < 2.6

Author: cxmcc

pymongo/mongo_replica_set_client.py

@@ -329,7 +329,7 @@ def schedule_refresh(self):
  """Override Monitor's schedule_refresh method
  raise exception as warning if thread is dead
  """
- if not self.is_alive():
+ if not self.isAlive():
  raise Exception("Monitor thread died unexpectedly, used with fork?")
  super(MonitorThread, self).schedule_refresh()