The switch to live drivers ease greenfield deployments by not requiring
deployers to explicitly set live drivers. The switch also helps
deployers identify production-ready from experimental drivers.
Experimental features like volume and distributor remain defaulted to
their noop drivers.
This patch also fixes some tests that were not mocked properly.
Change-Id: I1e4e3c4f0e4142fa0d0d1ac895b10e2349d79c20
f3b5e6e147