rst: only restore dgram socket queue once

In the case where there were multiple clients for a dgram socket, we were
restoring the queue for each client. Instead, we should pick one client and
she should restore the queue while the rest skip it.

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>