netd: fix oem chain init fail bug

Since NAT is not supported in ipv6, oem_nat_pre should not be
setup in ip6tables to ensure oemInitChain can be executed.

Bug: 120516786
Test: built, booted, netd unit test

Change-Id: I4ec23e661f0c17dd7895bc20ebc353f7bb30a9d3
1 file changed