mod_s2s_auth_dane: Fix traceback in DANE-TA check because unpack() moved
It moved into the table package in Lua 5.2, error happens when compat is
disabled or gone (ie 5.3+).
This happened in DANE-TA, which is disabled by default.
16 Your connection is encrypted using the %s protocol, which has been demonstrated to be insecure and will be disabled soon. Please upgrade your client.