Starting NATed jails always flushes ipfw table
There is a bug in the warden backend script startjail.sh that causes the ipfw filter table to always get flushed
before a new NAT rule is inserted. If you have more than one NATed jail the rules for those get lost then when the next jail is started.
The cause for this is that sysrc in the current FreeNAS by default reports the variable names and the values but the script only checks for the value.
Please see attached patch to fix the issue by telling sysrc to only report the values of firewall_enable and firewall_type