travis builds fail at HEAD at rc3 master with

  block/nbd-client.c: In function ‘nbd_read_reply_entry’:
  block/nbd-client.c:110:8: error: ‘ret’ may be used uninitialized in this function [-Werror=uninitialized]

fix it by initializing 'ret' to 0

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 block/nbd-client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/nbd-client.c b/block/nbd-client.c
index 422ecb4..02c8e20 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -70,7 +70,7 @@ static coroutine_fn void nbd_read_reply_entry(void *opaque)
 {
     NBDClientSession *s = opaque;
     uint64_t i;
-    int ret;
+    int ret = 0;
     Error *local_err = NULL;
 
     while (!s->quit) {
-- 
2.7.4