Merge branch 'bpf-bpftool-pinning-error-msg'

Jakub Kicinski says:

====================
First make sure we don't use "prog" in error messages because
the pinning operation could be performed on a map. Second add
back missing error message if pin syscall failed.
====================

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>