Use IPFW_DEFAULT_RULE instead of hardcoded value since now it is available.
Use IPFW_DEFAULT_RULE instead of hardcoded value since now it is
available.

MFC after:	5 days.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase