BUG: use correct setter for tensor value

Issue was:

AttributeError: 'vtkCommonCorePython.vtkFloatArray' object has no attribute 'SetTupleValue'
Traceback (most recent call last):
File "/Users/pieper/slicer4/latest/Slicer-superbuild/Slicer-build/lib/Slicer-4.5/qt-scripted-modules/DataProbe.py", line 260, in processEvent
self.layerValues[layer].setText(self.generateIJKPixelValueDescription(ijk, layerLogic))
File "/Users/pieper/slicer4/latest/Slicer-superbuild/Slicer-build/lib/Slicer-4.5/qt-scripted-modules/DataProbe.py", line 314, in generateIJKPixelValueDescription
return "<b>%s</b>" % self.getPixelString(volumeNode,ijk) if volumeNode else ""
File "/Users/pieper/slicer4/latest/Slicer-superbuild/Slicer-build/lib/Slicer-4.5/qt-scripted-modules/DataProbe.py", line 170, in getPixelString
value = self.calculateTensorScalars(tensor, operation=operation)
File "/Users/pieper/slicer4/latest/Slicer-superbuild/Slicer-build/lib/Slicer-4.5/qt-scripted-modules/DataProbe.py", line 553, in call
self.tensor_data.SetTupleValue(0, tensor)
AttributeError: 'vtkCommonCorePython.vtkFloatArray' object has no attribute 'SetTupleValue'

From: Steve Pieper <pieper@isomics.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@25254 3bd1e089-480b-0410-8dfb-8563597acbee