Fix bogus timestamp generated by XIM

Fix bogus timestamp generted by XIM due to uninitialized
data field. Also set appropriate serial, too.
Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=39367

Signed-off-by: Chiaki ISHIKAWA <ishikawa@yk.rim.or.jp>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>