unix: Fix double restoring of peerless unix sockets, which are peers for others

Since commit ea747b07 receive queue for
such DGRAM sockets restores twice: in open_unix_sk() and post_open_unix_sk().
It should be made only once. So, keep that commit logic only for sockets
without alive sender.
Signed-off-by: Kirill Tkhai <ktkhai@odin.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

sk-unix.c

@@ -1133,7 +1133,7 @@ static int open_unixsk_standalone(struct unix_sk_info *ui)
 
 		close(sks[1]);
 		sk = sks[0];
-	} else if (ui->ue->type == SOCK_DGRAM) {
+	} else if (ui->ue->type == SOCK_DGRAM && !ui->queuer) {
 		struct sockaddr_un addr;
 		int sks[2];