On such a domain, sign-in sync creates no account (the person gets an
ordinary authentication failure), changes nothing on an existing one,
and creates no group from a groups claim. Without the flag sync works as
before, and turning it off hands accounts back to sync with no restart.
Checked through synchronize_account itself; acceptance test 5 does the
same over OIDC once per-domain directories exist.
jcoffey-dev
940b42f3b4