As described by Stephan in the bug report, the XAggregation usage in
OSection of SvxFmDrawPage is broken; replace it by explicit forwarding
of the XDrawPage, XShapeGrouper, XFormsSupplier2 methods; it seems
to fix the crash here.  Also get rid of horrid refcount manipulation
etc. while at it.

Change-Id: Ib08830d2092bd2026db5b57c1c2e165b946889b3