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: I2ceee700ae274713bf7a6d5fae0d523e9feca481
Fixes-Bug: 10354
Reviewed-on: https://code.wireshark.org/review/3483
Reviewed-by: Guy Harris <guy@alum.mit.edu>