We remove a shard and detect whether it has completed or not.
If there are databases still left associated with the shard
we try to move them to a vacant shard.
Since we have to wait in a loop, we define a retry time in milliseconds
and a maximum number of retries. Warning, moving a large chunk might take a little time.Example: reallyRemoveShard(m, shard, retryTime, maxRetries)