Do not wipe all netd iptables rules in test mode

The NatController fail-safe which flushes the iptables when the ref
count reaches zero unintentionally wipes out all static rules setup
by init in bp-tools test mode.  Doing this flush is not necessary.

Change-Id: I37890e79cd701aa2e970958a246dfe7514a65c47
1 file changed