fix a bug in value painting for cell arrays

I wasn't rendering the correct values because I didn't have the right
ids. With small data the cellarray and polydata indices happened to
be the same. In general they won't be.

Change-Id: Id1186c8fab3b0ba0ff2e640a6fd3d6075f690516
Merge topic 'fix-cell-value-painter' into master

78108633 fix a bug in value painting for cell arrays