This is to fix a troublesome race condition occurring between Mineplexer
and Core. Simply put, the following steps occur normally:
1) Player logs in via Bungee
2) If there is no PlayerInfo entry, PlayerStats inserts a PlayerInfo entry
into Redis
3) CoreClientManager looks for the PlayerInfo entry and finds it
4) If the PlayerInfo entry was just inserted, it will have accountId=0.
CoreClientManager sees this and updates it to a valid accountId, then
reinserts into Redis
5) All is good
However, sometimes Step 3 occurs before Step 2 (perhaps latency to Redis
is a factor), and so CoreClientManager
sees a null entry and ignores it. Then, an invalid PlayerInfo entry is
inserted with accountId=0, which then breaks any SQL queries relying on an
valid accountId
