On restore we will use the peer's name to connect() the
socket back, so if there's no name dump should be aborted.

This situation happens when we create a socketpair(), fork
and dump only one task with one pair end.
Reported-by: Artem Kuzmitskiy <artem.kuzmitskiy@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>