Fix buffer overflow when serializing a closure object

Here is the JIRA page of this issue
https://bugs.tizen.org/jira/browse/TIVI-1889

Change-Id: I773a6d2d8f6fd02ff10c92450db1fa8a69544219
Signed-off-by: Chi Ding <chi.ding@mobica.com>
Closes: https://bugs.freedesktop.org/show_bug.cgi?id=65186