Fix texts that use writeConcern.w > 50

 [2020/02/06 18:18:57.519] ERROR [0.043s]: test_drop_collection (test_database.TestDatabase)

 [2020/02/06 18:18:57.519] ----------------------------------------------------------------------

 [2020/02/06 18:18:57.519] Traceback (most recent call last):

 [2020/02/06 18:18:57.519]   File "/data/mci/89656e6136f2401f533bcdcf3b3889b4/src/test/test_database.py", line 349, in test_drop_collection

 [2020/02/06 18:18:57.519]     db_wc.drop_collection('test')

 [2020/02/06 18:18:57.519]   File "/data/mci/89656e6136f2401f533bcdcf3b3889b4/src/pymongo/database.py", line 920, in drop_collection

 [2020/02/06 18:18:57.519]     session=session)

 [2020/02/06 18:18:57.519]   File "/data/mci/89656e6136f2401f533bcdcf3b3889b4/src/pymongo/database.py", line 630, in _command

 [2020/02/06 18:18:57.519]     client=self.__client)

 [2020/02/06 18:18:57.519]   File "/data/mci/89656e6136f2401f533bcdcf3b3889b4/src/pymongo/pool.py", line 604, in command

 [2020/02/06 18:18:57.519]     user_fields=user_fields)

 [2020/02/06 18:18:57.519]   File "/data/mci/89656e6136f2401f533bcdcf3b3889b4/src/pymongo/network.py", line 152, in command

 [2020/02/06 18:18:57.519]     parse_write_concern_error=parse_write_concern_error)

 [2020/02/06 18:18:57.519]   File "/data/mci/89656e6136f2401f533bcdcf3b3889b4/src/pymongo/helpers.py", line 159, in _check_command_response

 [2020/02/06 18:18:57.519]     raise OperationFailure(msg % errmsg, code, response)

 [2020/02/06 18:18:57.519] OperationFailure: w has to be a non-negative number and not greater than 50

 [2020/02/06 18:18:57.519] ----------------------------------------------------------------------

 [2020/02/06 18:18:57.519] Ran 2346 tests in 242.156s