sw: WW8 import: delete leaked SdrGrafObj (and temp file)

The SdrObject returned from SvxMSDffManager::GetShape() is owned by the
caller; since it's not inserted anywhere it has to be deleted.

Change-Id: Iaac6467592ec4151173a586a6dc71f9bc44b44f0

sw/source/filter/ww8/ww8par.cxx

@@ -4340,6 +4340,7 @@ void wwSectionManager::SetSegmentToPageDesc(const wwSection &rSection,
                 rFmt.SetFmtAttr(aSet.Get(RES_BACKGROUND));
             }
         }
+        SdrObject::Free(pObject);
     }
     wwULSpaceData aULData;
     GetPageULData(rSection, aULData);