Always return errors in ssl3_get_client_hello

Always return errors in ssl3_get_client_hello

If we successfully match a cookie don't set return value to 2 as this
results in other error conditions returning 2 as well.

Instead set return value to -2 which can be checked later if everything
else is OK.
(cherry picked from commit c56f5b8edfbcec704f924870daddd96a5f768fbb)