Non-async Elasticsearch kwargs sniffer_timeout should be dropped

[eLvErDe]

Hello,

After switching from classic driver to async one I kept the same init kwargs:

self.conn = AsyncElasticsearch(
    hosts=self.hosts,
    # http://elasticsearch-py.readthedocs.io/en/master/api.html?highlight=search#elasticsearch
    sniff_on_start=True,
    sniff_on_connection_fail=True,
    sniffer_timeout=60
)

This setting gives the traceback below. Removing sniffer_timeout make it work again. As the sniffing is probably handled completely different in async driver, I suggest dropping it from calling super.

 File "/usr/lib/python3.5/asyncio/futures.py", line 380, in __iter__
    yield self  # This tells Task to wait for completion.
  File "/usr/lib/python3.5/asyncio/tasks.py", line 304, in _wakeup
    future.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/asyncio/tasks.py", line 239, in _step
    result = coro.send(None)
  File "/usr/lib/python3/dist-packages/elasticsearch_async2/transport.py", line 136, in main_loop
    connection = self.get_connection()
  File "/usr/lib/python3/dist-packages/elasticsearch_async2/transport.py", line 53, in get_connection
    self.initiate_sniff()
  File "/usr/lib/python3/dist-packages/elasticsearch_async2/transport.py", line 35, in initiate_sniff
    self.sniffing_task.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/asyncio/tasks.py", line 239, in _step
    result = coro.send(None)
  File "/usr/lib/python3/dist-packages/elasticsearch_async2/transport.py", line 116, in sniff_hosts
    node_info = yield from self._get_sniff_data(initial)
  File "/usr/lib/python3/dist-packages/elasticsearch_async2/transport.py", line 86, in _get_sniff_data
    _, headers, node_info = t.result()
  File "/usr/lib/python3.5/asyncio/futures.py", line 293, in result
    raise self._exception
  File "/usr/lib/python3.5/asyncio/tasks.py", line 239, in _step
    result = coro.send(None)
  File "/usr/lib/python3/dist-packages/elasticsearch_async2/connection.py", line 55, in perform_request
    response = yield from self.session.request(method, url, data=body)
  File "/usr/lib/python3/dist-packages/aiohttp/helpers.py", line 91, in __iter__
    ret = yield from self._coro
  File "/usr/lib/python3/dist-packages/aiohttp/client.py", line 168, in _request
    raise RuntimeError('Session is closed')
RuntimeError: Session is closed

[sethmlarson]

This issue has been fixed upstream in elasticsearch[async] 7.8.0. See #81 for more information.