After deleting a face, check for unused edges and delete them. Fixes bug [#33891] projects.blender.org/tracker/?func=detail&aid=33891&group_id=9&atid=498
After deleting a face, check for unused edges and delete them. Fixes bug [#33891] projects.blender.org/tracker/?func=detail&aid=33891&group_id=9&atid=498