Fix a bug in clienthello processing

- Always process ALPN (previously there was an early return in the
  certificate status handling)

1.0.2 did not have the double-alert issue from master, but it seems
cleanest to pull in the structural change to alert handling anyway
and jump to f_err instead of err to send the alert in the caller.

(cherry picked from commit 70c22888

)

Reviewed-by: Emilia Käsper <emilia@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>