VclPtr related, dialog dtor is never called, so timer
is never stopped and timer refers to deleted parent
data

(cherry picked from commit 0943adb2)

Change-Id: I804ba082817802c0017e61c6b86c5d3694995ea8
Reviewed-on: https://gerrit.libreoffice.org/19926Reviewed-by: Maxim Monastirsky <momonasmon@gmail.com>
Tested-by: Maxim Monastirsky <momonasmon@gmail.com>
(cherry picked from commit 33df62ef)