BUG: Update EMSegment to fix regression introduced in labelmap node support

This commit fixes a regression introduced in r24291 (ENH: Use vtkMRMLLabelMapVolumeNode
class for labelmap volumes).

The issue has been found thanks to the following unused variable warning:

/home/jcfr/Projects/Slicer-Debug/EMSegment/CommandLineApplication/EMSegmentCommandLineFct.cxx:44:1: warning: unused parameter ‘labelMap’ [-Wunused-parameter]
AddNewScalarArchetypeVolume(vtkMRMLScene* mrmlScene,

EMSegment commit:

r17103 | jcfr | 2015-06-04 20:51:49 -0400 (Thu, 04 Jun 2015) | 4 lines

BUG: Fix unused variable warning fix regression introduced in previous commit.

Update AddNewScalarArchetypeVolume function to create either a scalar volume node
or a labelmap volume node.

Reviewed-by: Andras Lasso <lasso@queensu.ca>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@24299 3bd1e089-480b-0410-8dfb-8563597acbee