interactive.c: fix usage of potentially uninitialized variable

interactive.c: fix usage of potentially uninitialized variable

In function netsh_dns_cmd() it is possible to jump on a label and
call free() on uninitialized pointer. Move pointer initialization
above jump.

To fix a few warnings which are treated as errors with SDL enabled,
initialize pointers with NULL.

Signed-off-by: Lev Stipakov <lev@openvpn.net>
Acked-by: Selva Nair <selva.nair@gmail.com>
Message-Id: <1539022378-24485-1-git-send-email-lstipakov@gmail.com>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg17663.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>