In raft mode (auth-v2) we need to do atomic write after read as
we give stricter consistency guarantees. Instead of patching
legacy logic this commit adds different path as:
- old code may be less tested now so it's best to not change it
- new code path avoids quorum selects in a typical flow (passwords set)
There may be a case when user deletes a superuser or password
right before restarting a node, in such case we may ommit
updating a password but:
- this is a trade-off between quorum reads on startup
- it's far more important to not update password when it shouldn't be
- if needed password will be updated on next node restart
If there is no quorum on startup we'll skip creating password
because we can't perform any raft operation.
Additionally this fixes a problem when password is created despite
having non default superuser in auth-v2.
f85d73d405