Leases in breaking state are not supported. In that case criu will
report an error during the dumping. Also lock info in
/proc/<pid>/fdinfo should be presented (since kernel 4.1).

Before taking out new lease it modifies process fsuid to match file uid
(see fcntl F_SETLEASE).
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>