firewall4: update to latest Git HEAD

b54f462 fw4: parse traffic rules before forwarding rules
4d5af8b fw4: consolidate helper code
300c737 fw4: fix applying zone family restrictions to forwardings
eb9c25a tests: implement fs.opendir() mock interface
d30ff48 tests: fix mocked fs.popen() trace log
52831a0 fw4: improve flowtable handling
7cb10c8 fw4: disable "flow_offloading_hw" option for now
b2241a1 fw4: fix enabling NAT reflection rules for DNATs without explicit family

Signed-off-by: Jo-Philipp Wich <jo@mein.io>