With the change of the range of UIDs that is generated from the
automatic ID (-1), it became apparent that there is a potential problem
with these automatic IDs when upgrading: they may have changed, which
means that persistent files that exist outside of the rootfs suddenly
have a different owner.
Add a caveat section to the manual, as well as an explanation of how to
work around the problem.
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
[yann.morin.1998@free.fr: slight rewording]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>