Don't close socket if auth fails.

Also, check if the socket exists first...

Author: behackett

pymongo/mongo_replica_set_client.py

@@ -1122,12 +1122,15 @@ def __send_and_receive(self, member, msg, **kwargs):
  member.pool.maybe_return_socket(sock_info)
 
  return response
+ except OperationFailure:
+ raise
  except (ConnectionFailure, socket.error), why:
  host, port = member.pool.pair
  member.pool.discard_socket(sock_info)
  raise AutoReconnect("%s:%d: %s" % (host, port, str(why)))
  except:
- sock_info.close()
+ if sock_info:
+ sock_info.close()
  raise
 
  def __try_read(self, member, msg, **kwargs):