Use ObservableQuery.reobserve when polling, when possible.
Use ObservableQuery.reobserve when polling, when possible.

If we move polling logic from QueryManager into ObservableQuery, then we
will always have an ObservableQuery available to consume results when we
are polling, which should eliminate the non-ObservableQuery branch of this
condition.

apollographql/apollo-client,apollographql/apollo-client,apollostack/apollo-client,apollostack/apollo-client,apollostack/apollo-client