[python] Use new Python module structure of dune-common MR 960

CMakeLists.txt

@@ -23,6 +23,16 @@ add_subdirectory(dune)
 add_subdirectory(doc)
 add_subdirectory(cmake/modules)
 add_subdirectory(examples)
+
+# Since 2.9 Python bindings are enabled by default
+if(${dune-common_VERSION} VERSION_GREATER_EQUAL 2.9)
+  add_subdirectory(python)
+else()
+  if(DUNE_ENABLE_PYTHONBINDINGS)
+    add_subdirectory(python)
+  endif()
+endif()
+
 add_subdirectory(python)
 
 # finalize the dune project, e.g. generating config.h etc.