Don't reset traversal location in each iteration of box clip filter.

This causes the first cell in the clipped data to be output, rather
than the last, leading to bugs like:

http://paraview.org/Bug/view.php?id=14581

Change-Id: I57427d4e00997c13c0a5c188c30ffe6e59356527
Merge topic '14581-volume-render-bug' into master

a43fb6ae Don't reset traversal location in each iteration of box clip filter.