SF patch #806246:  use basestring where possible
(Contributed by George Yoshida.)
diff --git a/Lib/pkgutil.py b/Lib/pkgutil.py
index 4237371..fbd708a 100644
--- a/Lib/pkgutil.py
+++ b/Lib/pkgutil.py
@@ -50,7 +50,7 @@
     path = path[:] # Start with a copy of the existing path
 
     for dir in sys.path:
-        if not isinstance(dir, (str, unicode)) or not os.path.isdir(dir):
+        if not isinstance(dir, basestring) or not os.path.isdir(dir):
             continue
         subdir = os.path.join(dir, pname)
         # XXX This may still add duplicate entries to path on