iter: Fix pre-dump responce according to recent criu change
iter: Fix pre-dump responce according to recent criu change

There was a bug in criu RPC (not yet released) -- pre-dump
responded with dump resp. It was fixed (now it responds with
the pre-dump as well), fix in here.

Signed-off-by: Pavel Emelyanov <c9a32589e048e044184536f7ac71ef92fe82df3e@parallels.com>

marcosnils/p.haul,marcosnils/p.haul,avagin/p.haul,arthurlockman/p.haul,aburluka/p.haul,aburluka/p.haul,jne100/p.haul,arthurlockman/p.haul,aburluka/p.haul,xemul/p.haul,xemul/p.haul,biddyweb/phaul,aburluka/p.haul,arthurlockman/p.haul,jne100/p.haul,xemul/p.haul,arthurlockman/p.haul,jne100/p.haul,biddyweb/phaul,aburluka/p.haul,marcosnils/p.haul,biddyweb/phaul,jne100/p.haul,avagin/p.haul,arthurlockman/p.haul,xemul/p.haul,avagin/p.haul,xemul/p.haul,jne100/p.haul