Put setargv.obj back in the list of objects for mergecap.

This should enable automatic wildcard expansion and fix bug 10354.

Add the usual setargv.obj comment for reordercap, which also links with
setargv.obj.

Change-Id: If9c2b4ecf490dc263d3557a1cda24849a786d299
Fixes-Bug: 10354
Reviewed-on: https://code.wireshark.org/review/3484
Reviewed-by: Guy Harris <guy@alum.mit.edu>