title: I can't use aiohttp session if previous query failed with timeout
body: <p>I have a simple script that create async tasks for loading different pages. The first request fails with TimeoutError, and it causes next queries to fail too. But the second one has much longer timeout and should pass.</p>
  
  <p>Is it possible let other queries don't fail?</p>
  
  <pre><code>import aiohttp
  import asyncio
  import logging
  
  
  logging.basicConfig(level=logging.DEBUG,
                      format='%(asctime)s %(name)s %(levelname)s %(message)s')
  
  
  async def main():
      asyncio.ensure_future(
          load_page('https://www.netflix.com:5000'))
  
      asyncio.ensure_future(
          load_page('http://bash.im/', 10))
  
      asyncio.ensure_future(
          load_page('https://myshows.me/'))
  
      asyncio.ensure_future(
          load_page('http://www.lostfilm.tv/'))
  
  
  async def load_page(url, timeout=3):
      try:
          async with session.get(url, timeout=timeout) as response:
              text = await response.text()
              print(len(text))
  
      except Exception:
          logging.warning(type(e))
  
  
  if __name__ == '__main__':
      loop = asyncio.get_event_loop()
  
      conn = aiohttp.TCPConnector(limit=1)
      session = aiohttp.ClientSession(connector=conn, loop=loop)
  
      asyncio.ensure_future(main())
      loop.run_forever()
  </code></pre>
  
  <p>Log:</p>
  
  <pre><code>2017-06-26 13:57:37,869 asyncio DEBUG Using selector: EpollSelector
  2017-06-26 13:57:41,780 root WARNING &lt;class 'concurrent.futures._base.TimeoutError'&gt;
  2017-06-26 13:57:41,780 root WARNING &lt;class 'concurrent.futures._base.TimeoutError'&gt;
  2017-06-26 13:57:41,780 root WARNING &lt;class 'concurrent.futures._base.TimeoutError'&gt;
  2017-06-26 13:57:48,780 root WARNING &lt;class 'concurrent.futures._base.TimeoutError'&gt;
  </code></pre>