TLS: fix dissection of status_request_v2 hello extension

Bug: 10416
Change-Id: I58a3faef227f7eafd61942cafa6e38a17557ee61
Reviewed-on: https://code.wireshark.org/review/3865
Reviewed-by: Evan Huus <eapache@gmail.com>
Petri-Dish: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Pascal Quantin <pascal.quantin@gmail.com>