COMP: SimpleITK linkage failure

When building with clang on 10.9 where ITKv4 is a shared library,
a linking error occured for unfound symbols: NumericTraits< OutputPixelType >::Zero
but using the NumericTraits< OutputPixelType >::ZeroValue()
allows linkage to occur properly.

Change-Id: I496a41c102960b60c461adefdccc373b39dabb03
Merge topic 'FixZeroValue'

9ed7059 COMP: SimpleITK linkage failure