Update logic for flushing data to cloud.

Update logic for flushing data to cloud.

Do not force a commit of the most recent data, and instead just write out
whatever was last written to the journal.

This could be a win or a loss:
  - We do not need to force a sync of all data to the journal when we
    upload data to the cloud.
  - But, we may end up writing out old data, which we'll then need to
    overwrite a short time later.