For a lazy restore via userfaultfd the lazy-pages daemon
needs to know which pages exist, so that it knows when all
pages have finally been migrated so that the restored process
has all of its memory. Therefore it needs to know which pages
exist and it needs to parse the files in the dump result directory.

The existing criu functions are designed to be used by a 'normal'
restore and thus a lot of assumptions are made what has to be set up.

For the lazy-pages restore the complete 'restore' initialization is
not necessary and therefore the criu common code dependencies are
minimized with this commit.
Signed-off-by: Adrian Reber <areber@redhat.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>