PIVOT-891: Further fix to TextAreaSkin:  when a delete is done, reset
the anchor point to -1, because there is no longer an extended selection
process in progress, and the logic to properly extend the selection
around the anchor gets messed up.


git-svn-id: https://svn.apache.org/repos/asf/pivot/trunk@1604238 13f79535-47bb-0310-9956-ffa450edef68