Use provided env vars in up/down script.

Use provided env vars in up/down script.

This makes the down script work both as regular down script as well as
with the
down-root plugin. The up script is just changed for consistency.

Signed-off-by: Conrad Hoffmann <ch@bitfehler.net>
Acked-by: David Sommerseth <davids@openvpn.net>
Message-Id: <20170802181435.14549-2-ch@bitfehler.net>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg15165.html
Signed-off-by: David Sommerseth <davids@openvpn.net>
(cherry picked from commit 94c1ce22ebcc1f672bb80598afccc130aa01fafc)