Move private header files to <netlink-private/*>

This clarifies the seperation between public and private
header files.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Provide compat headers for removed private API

Some projects seem to have mistakenly included the private
API headers without actually needing them.

Provide dummy headers referring to the real headers to
provide backwards compatibility.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Fix test-cache-mngr test

Needs to include <netlink-private/cache-api.h>

Reported-by: Jeroen Roovers <jer@gentoo.org>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Fix build warnings of nl-(qdisc|class|cls)-add

Reported-by: Jeroen Roovers <jer@gentoo.org>
Signed-off-by: Thomas Graf <tgraf@suug.ch>