Silence uninitialized mem warning on disk_util send

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/server.c b/server.c
index e4793f7..9cbe555 100644
--- a/server.c
+++ b/server.c
@@ -770,6 +770,8 @@
 
 	dprint(FD_NET, "server: sending disk_util %d\n", !flist_empty(&disk_list));
 
+	memset(&pdu, 0, sizeof(pdu));
+
 	flist_for_each(entry, &disk_list) {
 		du = flist_entry(entry, struct disk_util, list);