commit 0647e708 upstream.

Remove __nf_conntrack_find() from headers.

Fixes: dcd93ed4 ("netfilter: nf_conntrack: remove dead code")
Signed-off-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>