Make network_policy flake8 compatible.

Change-Id: I1b188cf206a49eb951c2fb7a9f60dbf855cf822d
Make NetworkPolicy use vnc_lib instead of neutron client.

Change-Id: I6cdfb8ee7932e661b6021c821b6e5b0c628b7870
Merge pull request #6 from jswiders/network_policy

Network policy