Fallback if lsb_release -si does not return Ubuntu, Debian or Raspbian
Fallback if lsb_release -si does not return Ubuntu, Debian or Raspbian

Adds a fallback if lsb_release -si returns anything else than Ubuntu, Debian or Raspbian.

Should solve https://github.com/arakasi72/rtinst/issues/495. Needs testing and confirmation.
arakasi72/rtinst