Update Debian repo to retrieve signed Release file

After bootstraping a Debian image, the repository keys
are installed to verify the packages signatures, but the
Release signature file is missing. Updating the repo,
will retrieve a new InRelease file (inline signed).

Change-Id: I14f0d22cc9c72be9b07f3708270359bc8cff112d
Merge "Update Debian repo to retrieve signed Release file"