Fixed HDF5 Find module error that caused no list to be passed into remove...

Fixed HDF5 Find module error that caused no list to be passed into remove duplicates when HDF5 is not found.

Modules/FindHDF5.cmake

@@ -253,10 +253,18 @@ else()
     # We may have picked up some duplicates in various lists during the above
     # process for the language bindings (both the C and C++ bindings depend on
     # libz for example).  Remove the duplicates.
-    list( REMOVE_DUPLICATES HDF5_INCLUDE_DIR )
-    list( REMOVE_DUPLICATES HDF5_LIBRARIES_DEBUG )
-    list( REMOVE_DUPLICATES HDF5_LIBRARIES_RELEASE )
-    list( REMOVE_DUPLICATES HDF5_LIBRARY_DIRS )
+    if( HDF5_INCLUDE_DIR )
+        list( REMOVE_DUPLICATES HDF5_INCLUDE_DIR )
+    endif()
+    if( HDF5_LIBRARIES_DEBUG )
+        list( REMOVE_DUPLICATES HDF5_LIBRARIES_DEBUG )
+    endif()
+    if( HDF5_LIBRARIES_RELEASE )
+        list( REMOVE_DUPLICATES HDF5_LIBRARIES_RELEASE )
+    endif()
+    if( HDF5_LIBRARY_DIRS )
+        list( REMOVE_DUPLICATES HDF5_LIBRARY_DIRS )
+    endif()
 
     # Construct the complete list of HDF5 libraries with debug and optimized
     # variants when the generator supports them.