firewall: correct acquisition result of DENY rule

When blocked packet logging is enabled,
 GET rest command shows DENY rules as 'ALLOW' before.

This patch improves it.

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>