Define distro that is to be returned by default

[ocelotl]

          This seems to make the default behavior to be "return the first distro if there is no selected distro. This is a behavior we want to avoid, if the distro is not specifically selected a default fixed distro should be returned. Maybe this is what happens because a default distro is always set as the first distro but this function does not make that very obvious.

Originally posted by @ocelotl in #1823 (comment)