python: remove star imports

Star imports are discouraged and break pyflakes.

I'm happy to report that pyflakes finds no issues ;)

tools/make-directive-index.py

@@ -21,7 +21,7 @@
 import sys
 import collections
 import re
-from xml_helper import *
+from xml_helper import xml_parse, xml_print, tree
 from copy import deepcopy
 
 TEMPLATE = '''\