Fix problem in count where it was passing ["ns missing"] as the count param rather than the intended allowable_errors param to database.command()

Author: Rick Copeland

pymongo/cursor.py

@@ -307,7 +307,7 @@ def count(self, with_limit_and_skip=False):
  if self.__skip:
  command["skip"] = self.__skip
 
- response = self.__collection.database.command(command, ["ns missing"])
+ response = self.__collection.database.command(command, allowable_errors=["ns missing"])
  if response.get("errmsg", "") == "ns missing":
  return 0
  return int(response["n"])