Update elements to use os-svc-daemon -i.

Globally updates all the elements so we explicitly set the
virtualenv install directory with the os-svc-daemon -i option.

This allows us to support both isolated and shared venvs
(which some people would like to use).

Change-Id: Ie264ff58d7e733542ba32853f5c0f593b64ffe4a
Merge "Update elements to use os-svc-daemon -i."