Respect return value from nbd_client()

Signed-off-by: Jes Sorensen <[email protected]>
Signed-off-by: Blue Swirl <[email protected]>
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 9cc8f47..67ce50b 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -417,7 +417,10 @@
 
             show_parts(device);
 
-            nbd_client(fd);
+            ret = nbd_client(fd);
+            if (ret) {
+                ret = 1;
+            }
             close(fd);
  out:
             kill(pid, SIGTERM);