COMP: Change to tclsh does not work on windows

The change to use tclsh rather than the vtk executable does not work
on windows.

This patch reverts that change.

Change-Id: I048e8c62a547a2a04a2923df084016b451c636d3
Merge topic 'BackoutTCLPatch' into master

13ab3b0e COMP: Change to tclsh does not work on windows