COMP: runTimePostProcessing build with VTP+MPI fails (#1231)

- incorrectly uses paraview include dirs instead of the more universal
  vtk include dirs for the MPI test.

src/runTimePostProcessing/CMakeLists-Project.txt

@@ -27,7 +27,7 @@ file(WRITE ${test_file}
 try_compile(FOAM_USING_VTK_MPI
     ${CMAKE_CURRENT_BINARY_DIR} ${test_file}
     LINK_LIBRARIES vtkParallelMPI
-    CMAKE_FLAGS "-DINCLUDE_DIRECTORIES=${PARAVIEW_INCLUDE_DIRS}"
+    CMAKE_FLAGS "-DINCLUDE_DIRECTORIES=${VTK_INCLUDE_DIRS}"
 )
 if (FOAM_USING_VTK_MPI)
     add_definitions(-DFOAM_USING_VTK_MPI)