pb: Rewrite object reading to use pb-descs

The pb_read thing is no longer a macros. This will allow to
factor out objects collecting on restore.

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

net.c

@@ -155,7 +155,7 @@ static int restore_links(int pid)
 	}
 
 	while (1) {
-		ret = pb_read_eof(fd, &nde, net_device_entry);
+		ret = pb_read_one_eof(fd, &nde, PB_NETDEV);
 		if (ret <= 0)
 			break;