~SwModify: do not silently tolerate clients registered past death

- Make SwFormat/SwContentNode explicitly resetting the page desc. before
death instead of SwFormatPageDesc trying to do that on the dying hint:
* the dying hints is send _after_ the SwFormat/SwContentNode dtor are
completed, so the RTTI magic did not work anyway
* simply resetting the attribute in a final dtor and make
SwFormatPageDesc just check to never get a dying hint (because it
should have been destructed by reset) is a lot less errorprone.

Change-Id: I231f1729729491ba7544e5ba93d81192b212e2ae
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/108648
Tested-by: Jenkins
Reviewed-by: Bjoern Michaelsen <bjoern.michaelsen@libreoffice.org>

0 files changed, 0 insertions, 0 deletions