Move run_up_down() to init.c

Move run_up_down() to init.c

This function is only used in init.c, and is not easy to fit into a
specific category because it both runs scripts and plugin hooks.  Making
it static in init.c is probably the best place for this function.

(I think we should find a better place for everything currently in misc.c,
and get rid of it all together.  This patch is part of that effort.)

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Antonio Quartulli <a@unstable.cc>
Message-Id: <1502811586-19578-1-git-send-email-steffan.karger@fox-it.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15256.html
Signed-off-by: David Sommerseth <davids@openvpn.net>
(cherry picked from commit 4a9d1d70d5b0ff04dbf26ba7e679733a54c694b6)