Marked vtkPOPMatrices.cxx to not be client-server wrapped.

vtkPOPMatrices is a helper class and shouldn't be client-server
wrapped. I think this was causing the build issue.
Merge remote-tracking branch 'github/vtkPOPMatrices_build_issue' into uvcdat-master

* github/vtkPOPMatrices_build_issue:
  Marked vtkPOPMatrices.cxx to not be client-server wrapped.