/proc/locks can contain a wrong pid for a lock and we always need to
check this fact.  Starting with the 4.1 kernel, locks are reported
in fdinfo.

v2: rebase to the curret master
    skip note_file_lock()
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>