[0.89-fb] Improve retry logic in HTableMultiplexer.HTableFlushWorker

The failed puts in HTableMultiplexer.HTableFlushWorker are immediately resubmitted in the original queue. This queue is being flushed every 100ms (default configuration) and the maximal retry of a failed put is by default 10 times (client configurable). That leaves us with ~1 second to complete a Put (with default configuration). We can improve this by gradually increasing the time for retrying, each time when the put fails. (example: first time retry after 100ms, then after 200ms, 400ms, etc).