minor fix to MHD test

IO/Testing/Tcl/CMakeLists.txt

@@ -19,7 +19,6 @@ IF (VTK_USE_RENDERING)
       gaussian
       caffeine
       TestXYZMol
-      TestMHD
       )
       ADD_TEST(${tfile}-image ${VTK_EXECUTABLE}
         ${VTK_SOURCE_DIR}/Common/Testing/Tcl/rtImageTest.tcl 
@@ -36,6 +35,16 @@ IF (VTK_USE_RENDERING)
 
 ENDIF (VTK_USE_RENDERING)
 
+# if we have parallel then add TestMHD 
+IF (VTK_USE_PARALLEL)
+  ADD_TEST(TestMHD-image ${VTK_EXECUTABLE}
+    ${VTK_SOURCE_DIR}/Common/Testing/Tcl/rtImageTest.tcl 
+    ${VTK_SOURCE_DIR}/IO/Testing/Tcl/TestMHD.tcl
+    -D ${VTK_DATA_ROOT}
+    -V Baseline/IO/TestMHD.png
+    -A ${VTK_SOURCE_DIR}/Wrapping/Tcl)
+ENDIF (VTK_USE_PARALLEL)
+
 ADD_TEST(TestEmptyXML ${VTK_EXECUTABLE}
          ${VTK_SOURCE_DIR}/IO/Testing/Tcl/TestEmptyXML.tcl)