firewalllog.dat: Fix for bug#13492 - include chain in the exported output

firewalllog.dat: Fix for bug#13492 - include chain in the exported output

- The regex code does not extract out the chain and so it is missed off from the log output
   when it is exported.
- Changed code tested out on my vm testbed and confirmed to work and include the chain in
   the output.

Fixes: Bug13492
Tested-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Bernhard Bitsch <bbitsch@ipfre.org>