When a retrieval hangs forever, we need to lotus client cancel-retrieval before retry

[ghost]

This issue is a breakout of the comment here.

The basic problem is that some retrievals will hang forever, and we need the dealbot both to timeout and then actually cancel the deal (API equivalent of lotus client cancel-retrieve --deal-id 1600000000000000000) before it retries. Otherwise, all subsequent retries will fail because the original retrieval is still running as far as lotus is concerned.

[willscott]

this is blocked on dealid not being exposed by lotus.
Needs filecoin-project/lotus#6415 resolved to be able to do this.