Use the policy 'rules' attribute instead of adding child rules.
This is expected to have better performance on the NSX side.
This patch re-itroduce the fix from: I213616a8b47f11adb1a897568746885f3e77078c
but this time with a flag to not break stuff
Change-Id: Ib6361575642fa96a93dd49107ece1f120a6e61b2