2004 privsep caused "tcpdump -r" to became a priviledged operation because

2004 privsep caused "tcpdump -r" to became a priviledged operation because
we felt chroot-containment was also necessary for off-line analysis.  Today
use of pledge "stdio" for the packet parser acts as an even better sandbox.
We can therefore silently ignore chroot setup failure, and regain tcpdump -r
support.

Result of a discussion with tedu -- which probably happened because we
became aware of the laughable retarded -Z option in upstream tcpdump.
ok tedu sthen guenther stsp