Also found an error in SdrObjCustomShape::TRGetBaseGeometry when MirrorY was used

(cherry picked from commit 4116c33b)

Conflicts:
	xmloff/source/draw/ximpshap.cxx
	xmloff/source/draw/ximpshap.hxx

Change-Id: Id85ae4c4f5e26d53d501c72b84fc0e1b5cfe23b2