Merge branch 'bpf-bpftool-various-fixes'

Jakub Kicinski says:

====================
Two small fixes here to listing maps and programs.  The loop for showing
maps is written slightly differently to programs which was missed in JSON
output support, and output would be broken if any of the system calls
failed.  Second fix is in very unlikely case that program or map disappears
after we get its ID we should just skip over that object instead of failing.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>