Merge branch 'bpf-samples-improvements'

Jakub Kicinski says:

====================
This set is next part of a quest to get rid of the bpf_load
ELF loader.  It fixes some minor issues with the samples and
starts the conversion.

First patch fixes ping invocations, ping localhost defaults
to IPv6 on modern setups. Next load_sock_ops sample is removed
and users are directed towards using bpftool directly.

Patch 4 removes the use of bpf_load from samples which don't
need the auto-attachment functionality at all.

Patch 5 improves symbol counting in libbpf, it's not currently
an issue but it will be when anyone adds a symbol with a long
name. Let's make sure that person doesn't have to spend time
scratching their head and wondering why .a and .so symbol
counts don't match.

v2: - specify prog_type where possible (Andrii).
====================

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