and fix potential leak on early return in SdrDragView::BegDragObj

Change-Id: I707be6e2c7dc2c251f37447fe3cd98c4b50b59d1
Reviewed-on: https://gerrit.libreoffice.org/53751Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>