Just update password hash without validating

Fixes #11097

If your password hash changed (becuse your are on 7.2 and we moved to
ARGON2). Then we shold not 'set a new password' but just update the
hash. As else we invoke the password policy again which might lock out
users.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>