The auth intialization path contains a fixed 15s delay,
which used to work around a couple of issues (#3320, #3850),
but is right now quite useless, because a retry mechanism
is already in place anyway.
This patch speeds up the boot process if authentication is enabled.
In particular, for a single-node clusters, common for test setups,
auth initialization now takes a couple of milliseconds instead
of the whole 15 seconds.
Fixes#8648Closes#8649
c1cb7d87e1