Hi Harald,

The function merge_opts doesn't release previously merged options, this 
results in a memory leak. This increases considerably memory comsumption 
in iptables-restore.

This patch fixes a leak on error paths as well.

Results: With my testcase ruleset of ~10.000 rules and this patch, 
iptables-restore reduces memory consumption by 66 percent. It's passed 
from eating ~12 Mbytes to ~4 Mbytes. This can be interesting for 
embedded devices running iptables.

--
Pablo