Plan 1: Start a server without scrypt extension, enable user/pass
authentication. Check 'Password' Settings page, see that 'bcrypt' or
'iterated-md5' is the current hashing algorithm. Enable `scrypt`
extension in `php.ini` and restarted server. Was prompted to upgrade
password, as `scrypt` is now available.
Plan 2: Start a server **with** scrypt extension enabled in `php.ini`,
enable user/pass authentication. Check 'Password' Settings page, and
scrypt is already selected as the default.