Comment 2 for bug 1312731

PlainBox has multi-session API (ability to have many sessions and not remove the last one over and over) but almost no clients actually use it. This is also complicated by checkbox-gui/dbus using the single-session API and having some hard baked things based on that design (so it's possible but more costly to change that).

In addition, before we really use multi-session API for everything we should add a tool (plainbox subcommand?) that could list and remove sessions that we don't need anymore.