Added policy checks for add interface and remove interface
Added policy checks for add interface and remove interface

Fixes bug 1042037
admin_only policy didn't works, so policy checks
for add interface and remove interface needed.
Also updated policy.json

Change-Id: Ifec281250ccbe1680a3e634f4efdb7ba7ef3ec94

budnyjj/ofagent,yamt/networking-ofagent,budnyjj/ofagent,yamt/networking-ofagent-old3