Xdmf3 was failing to build when using system HDF5.

When using system HDF5, xdmf3 was failing to build since it was
attempting to link against -lvtkhdf5. The issue was coming from the use
of vtkxdmf3_LINK_DEPENDS. That piece of code seems a little out of place
since no other third party module does that. The CMakeLists.txt already
handled all link dependencies properly, hence this was not necessary and
causing the issue.

ThirdParty/xdmf3/vtkxdmf3/core/CMakeLists.txt

@@ -154,7 +154,7 @@ set(XdmfCoreSources
 add_library(XdmfCore ${LIBTYPE} ${XdmfCoreSources})
 link_directories(${XDMF_LIBRARY_DIRS})
 
-target_link_libraries(XdmfCore ${XDMF_LIBRARIES} ${vtkxdmf3_LINK_DEPENDS})
+target_link_libraries(XdmfCore ${XDMF_LIBRARIES})
 vtk_target_install(XdmfCore)
 
 if(WIN32)