Try to undo iptables rules if a command fails.

As per review comments at:
https://googleplex-android-review.git.corp.google.com/#/c/504240/5/server/NatController.cpp@194

Bug: 15413694
Bug: 15413741
Change-Id: I99e2f83792fa81498447e4c03f5f8be1d2c43b7d
1 file changed
tree: 11b2ef7fe4e943b728b4b8769ab5f6010b35548f
  1. client/
  2. include/
  3. server/