qemu-sockets: Fix parsing of the inet option 'to'.

Having a qemu command line argument like "-vnc 127.0.0.1:0,to=99" is broken.
This have been break with commit 879e45c7.
Signed-off-by: NAnthony PERARD <anthony.perard@citrix.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Nmalc <av1474@comtv.ru>

qemu-sockets.c

@@ -529,8 +529,9 @@ static InetSocketAddress *inet_parse(const char *str, Error **errp)
     optstr = str + pos;
     h = strstr(optstr, ",to=");
     if (h) {
-        if (1 != sscanf(str, "%d%n", &to, &pos) ||
-            (str[pos] != '\0' && str[pos] != ',')) {
+        h += 4;
+        if (sscanf(h, "%d%n", &to, &pos) != 1 ||
+            (h[pos] != '\0' && h[pos] != ',')) {
             error_setg(errp, "error parsing to= argument");
             goto fail;
         }