Jessie: Ensure that the persistent volume is not managed by GNOME while it's being created
It could be that when t-p-s is creating the persistent volume, udisks2/Nautilus automount it and a notification is displayed (see #5938 (closed) for a similar problem that was addressed in Tails Installer). We should check if that’s the case, and if it is, evaluate what are the potential problems it would cause. And if we need to prevent that:
- see how gparted handles this: https://bugzilla.gnome.org/show_bug.cgi?id=745349 and https://git.gnome.org/browse/gparted/commit/?id=4acb8e4fbb9e01d33cc1e9fd89686a3818050690
- see if we can use a trick similar to the Tails Installer’s one to make udisks2 temporarily mark the newly created volume as hidden, and revert that trick before quitting t-p-s.