Track the right number of streams, and cancel the push when the request is cancelled.
Track the right number of streams, and cancel the push when the request is cancelled.

This was broken in a422f394bb4660c98f7d692e16c3cc28747b7abd.

Signed-off-by: Tom Wilkie <4d61d701e7f49021437d91fbf6a1826e6d4e51de@gmail.com>

grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki,grafana/loki