Per http://www.vtk.org/Bug/view.php?id=13597
When you turn on USE_SYSTEM_HDF5, especially with stock ubuntu,
CMake's FindHDF5 may return debug;<a>;optimized;<b> where either
<a> or <b> is empty (or <a>==<b> in which case a late remove
results in the same situation). When that happens
VTK will not compile under the empty config type.

In cmake 2.8.12.2, FindHDF5 is fixed, so when vtk's min cmake
reaches that this patch should be removed.

Change-Id: I29c55904f5f8e1d6797899eec033872dd377ea35