COMP: Fix default wrapping with all modules

My previous patch (http://review.source.kitware.com/#/c/15885/) broke the wrappings
when starting from an empty build dir, as the ITKGroup_ variables are only set when
ITK_BUILD_DEFAULT_MODULES was set once to OFF.

This will fix the errors on the dashboard.

Change-Id: I3b0d514caba3444ffeaa6837a915481877a9ca1d
Merge topic 'FixWrappingBuildALL'

e6f6e15a COMP: Fix default wrapping with all modules