Squelch a warning.

Change-Id: Id27a6447dba9b6eda07933139a3f07edd71c8fd6
Reviewed-on: https://code.wireshark.org/review/2872
Reviewed-by: Guy Harris <guy@alum.mit.edu>
(cherry picked from commit ab5d1cfa20b3047ed062bc3b9fbf85d396ae7e63)
Reviewed-on: https://code.wireshark.org/review/2873