iov: avoid "orig_len may be used unitialized" warning

Signed-off-by: NWenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NMichael Tokarev <mjt@tls.msk.ru>
(cherry picked from commit 2be178a4)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

util/iov.c

@@ -181,13 +181,11 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
             assert(iov[niov].iov_len > tail);
             orig_len = iov[niov].iov_len;
             iov[niov++].iov_len = tail;
-        }
-
-        ret = do_send_recv(sockfd, iov, niov, do_send);
-
-        /* Undo the changes above before checking for errors */
-        if (tail) {
+            ret = do_send_recv(sockfd, iov, niov, do_send);
+            /* Undo the changes above before checking for errors */
             iov[niov-1].iov_len = orig_len;
+        } else {
+            ret = do_send_recv(sockfd, iov, niov, do_send);
         }
         if (offset) {
             iov[0].iov_base -= offset;