9b253e7ea7
Give the range to 'importdescriptors' when re-importing a descriptor for rescanning. This is because the range must include the range of the descriptor being updated. Secondly, it is possible that the combination of our timeout-to-1s hack and our retry logic trigger an edge case: we would retry after successfully triggering a rescan, and therefore panic on a "a rescan is already ongoing" error. Instead check before starting that we aren't rescanning already, and assume that such an error after triggering the rescan is because we succeeded. That's racy but only reasonably so (as long as we don't crash, which isn't the case here).