Update "raspbian.sh" to force keyring usage so it can safely switch to mirrordirector.raspbian.org
Update "raspbian.sh" to force keyring usage so it can safely switch to mirrordirector.raspbian.org

This service is documented at https://www.raspbian.org/RaspbianMirrors#The_mirror_redirection_system, and hopefully will allows us to be less heavy on archive.raspbian.org.

debuerreotype/debuerreotype