Now always restore from a full backup only, the standard has already
been switched in the scope of this ticket a while back.  The section
restore could be improved, but it's not really worth doing this in
the old code anymore.  Hopefully the last change of its kind here.

(cherry picked from commit 14fabe46)
(cherry picked from commit 0dad9094)
(cherry picked from commit e3196586)
(cherry picked from commit 96820738)
(cherry picked from commit d3c7d74c)