Don't use framework permission strings for netd permissions.

These framework permission strings were being used as arbitrary labels
that mapped to netd permissions that have completely different meaning.
This leads to confusion, so use different strings.

This is being cherry picked from lmp-mr1-dev to lmp-dev to fix failures
when creating restricted networks due to prior back-port a1204421.

Bug: 21900139
Bug: 18194858
Change-Id: Ib3ec377ab26ce904d3d4678f04edec6cb1260517
(cherry picked from commit 0f8f1208)