This is now handled in Dialog::dispose

Change-Id: If6703dbf1fa02c3d83debcc17eba3c6b1ee49a1c
Reviewed-on: https://gerrit.libreoffice.org/48622Reviewed-by: Jan Holesovsky <kendy@collabora.com>
Tested-by: Jan Holesovsky <kendy@collabora.com>
(cherry picked from commit cc9ca93c)
Reviewed-on: https://gerrit.libreoffice.org/57506
Tested-by: Jenkins