Bypass medic-api beneath /dashboard to avoid 502s and failed updates.

During an update, gardener shuts down and restarts the modules it supervises,
including medic-api. If we're accessing the update interface through medic-api,
we're going to have a bad time.

Toward https://github.com/medic/medic-webapp/issues/625.
Merge branch 'dev' of https://github.com/browndav/medic-os into concierge-refactor