Forbid VPC-related functionality for usage without Neutron.

Change-Id: Ie67ffadea38e9d72236493d14d4e7cf9411de54a
Use Describer for instances

Change-Id: Id998b85c492f64705474cc21c85262d6f9303cca
Fix describe behavior of selected kinds

Change-Id: I4ec77c7fd1e84e7056887013f334df708755c66c
Merge "Use Describer for instances"
Merge "Fix describe behavior of selected kinds"