this bug was introduced in

    commit a754294a
    use rtl::Reference in SwDocFac instead of manual acquire/release

fix it by using automatic ref-counting (i.e. rtl::Reference) everywhere.

Note that the logic in SwViewShell::~SwViewShell is somewhat
interesting.
From my reading of it, it was previously potentially calling
getIDocumentLayoutAccess on an SwDoc that had just been deleted.

So if there is a problem with this commit I would look there first.

Change-Id: I95b6b7e7523689c8b56063af642c3a84cbdcd331
Reviewed-on: https://gerrit.libreoffice.org/43131Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>