This commit fixes a bug that would cause us to request more sessions
that needed from the session negotiator. With the current stat ticker,
we'd ask the negotiator for a new session every 30s if session
session negotiation did not return before printing the stats. Now we'll
avoid requesting to sessions by jumping back into the select loop.
Now that the committed and acked updates are persisted across restarts,
we will use them to filter out duplicate commit heights presented by the
client.
