BUG: Ensure itcl library is fixed when packaging on MacOSX - Attempt 0000002

This commit is a follow up of r24467 and fixes the following packaging
error:

warning: target '/Volumes/Dashboards/Experimental/Slicer-Release/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.4.0-2015-07-26-macosx-amd64/Slicer.app/Contents/lib/TclTk/lib/libitcl4.0.1.dylib' does not exist...
/usr/bin/otool: can't open file: /Volumes/Dashboards/Experimental/Slicer-Release/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.4.0-2015-07-26-macosx-amd64/Slicer.app/Contents/lib/TclTk/lib/libitcl4.0.1.dylib (No such file or directory)
otool: can't open file: /Volumes/Dashboards/Experimental/Slicer-Release/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.4.0-2015-07-26-macosx-amd64/Slicer.app/Contents/lib/TclTk/lib/libitcl4.0.1.dylib (No such file or directory)
install_name_tool: can't open file: /Volumes/Dashboards/Experimental/Slicer-Release/Slicer-build/_CPack_Packages/macosx-amd64/DragNDrop/Slicer-4.4.0-2015-07-26-macosx-amd64/Slicer.app/Contents/lib/TclTk/lib/libitcl4.0.1.dylib (No such file or directory)

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24471 3bd1e089-480b-0410-8dfb-8563597acbee