src: Initialize struct stmt in _match and _target functions.

src: Initialize struct stmt in _match and _target functions.

Initialize structure stmt with stmt_alloc in netlink_parse_target and
netlink_parse_match functions. This patch fixes the gcc warning:

‘stmt’ may be used uninitialized in this function.

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>