Remove unused ThreadIdent.get() call PYTHON-509

Author: A. Jesse Jiryu Davis

pymongo/pool.py

@@ -324,8 +324,6 @@ def in_request(self):
  return bool(self._request_counter.get())
 
  def end_request(self):
- tid = self._ident.get()
-
  # Check if start_request has ever been called in this thread / greenlet
  count = self._request_counter.get()
  if count: