Remove calls to policy.check and policy.enforce from plugin code
Remove calls to policy.check and policy.enforce from plugin code

Completes blueprint make-authz-orthogonal

This patch removes a few explicit policy checks recently added to
the plumgrid and cisco plugins.
They are not necessary as the same checks are already performed
by the policy engine.

Change-Id: Ie99f5fa6ad4a9568b050827bc479a62dd40e18ac

CiscoSystems/networking-cisco,openstack/networking-cisco,Tehsmash/networking-cisco,noironetworks/networking-cisco,cisco-openstack/networking-cisco,Gitweijie/first_project,nikolay-fedotov/networking-cisco,Gitweijie/first_project,noironetworks/networking-cisco,CiscoSystems/networking-cisco,hareeshpc/networking-cisco,openstack/networking-cisco,Tehsmash/networking-cisco,cisco-openstack/networking-cisco,hareeshpc/networking-cisco