BUG: warning was displayed via vtkErrorMacro

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22173 3bd1e089-480b-0410-8dfb-8563597acbee
BUG: warning message was incorrectly labeled as error

git-svn-id: http://svn.slicer.org/Slicer4/trunk@22174 3bd1e089-480b-0410-8dfb-8563597acbee