It only compared nodes instead of SwPositions, thus refusing to delete
anything anchored at the last content node. Also, select-all makes
rEnd point to the last content node, after its content. So if
an anchor-to-char image is anchored at the end of the paragraph,
it points to this place, too, so that must be checked.

Change-Id: Ie0ba6ed59f47e59492ad88577392884cadb52106