Don't wait for upgrades to be checked when the network is unplugged.
Merge branch 'bugfix/6592-fix-races-with-check-for-upgrades' into experimental
Include /home/amnesia/.xsession-errors in WhisperBack bug reports.

This captures the Tails Upgrader errors and debugging information.
Merge branch 'feature/6508-incremental-upgrades-phase-four' into experimental