Fix Scenario: Upgrading an old Tails USB installation from another Tails USB drive
Closes Installer does not detect target drive for clon... (#18840 - closed)
This also changes the way tails-installer logs are collected: now they are both sent to a file AND to syslog. This is suboptimal:
- why not sending them only to syslog?
- which could avoid us open the terminal at all, thus testing it as a "real" user would do
- if we don't want to send them to syslog, we should make sure sending them to a file works better.