homebrew: 1.5 - fix for buffer overruns with ipfw

My Mac running Snow Leopard 10.6.8 has been attacked by ssh login attempts from over 30 IP addresses which got blacklisted, which caused buffer overruns (SIGBUS) assembling the ipfw command in sshguard 1.5 from homebrew. Once I fixed those it exceeded limits in ipfw. Here is a patch that fixes all of them. It has been sent to the upstream maintainers but they don't seem to be very active in the past few months.