Get it compiling again.

Remove set-but-not-used variable.
Mark a parameter as unused.

Change-Id: I7c3af353da2967e5d611deb2cb027a9e30e54bdf
Reviewed-on: https://code.wireshark.org/review/3741
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>