remove unnecessary return; statement

Change-Id: Icefbaf632e888e84bcb2cc20ae3a6c4744b82fae
Reviewed-on: https://code.wireshark.org/review/3251
Petri-Dish: Martin Kaiser <wireshark@kaiser.cx>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Martin Kaiser <wireshark@kaiser.cx>
Tested-by: Martin Kaiser <wireshark@kaiser.cx>