http: Put exception in the queue in connection_lost

The client fiber may already be blocked on the queue (in getresponse)
when connection_lost is invoked.

The code in getresponse already handles getting an exception from the
queue.

lib/gruvi/http.py

@@ -1082,6 +1082,7 @@ def connection_lost(self, exc):
             if self._message:
                 self._message.body.buffer.feed_error(exc)
         self._error = exc
+        self._queue.put_nowait(exc)
 
     @property
     def writer(self):