some py3 fixes

plone/app/discussion/catalog.py

@@ -12,7 +12,6 @@ from plone.uuid.interfaces import IUUID
 from Products.CMFCore.interfaces import IContentish
 from Products.CMFPlone.utils import safe_unicode
 from Products.ZCatalog.interfaces import IZCatalog
-from string import join
 
 
 MAX_DESCRIPTION = 25
@@ -77,7 +76,7 @@ def creator(object):
 @indexer(IComment)
 def description(object):
     # Return the first 25 words of the comment text and append ' [...]'
-    text = join(object.getText(targetMimetype='text/plain').split()[:MAX_DESCRIPTION])
+    text = ' '.join(object.getText(targetMimetype='text/plain').split()[:MAX_DESCRIPTION])
     if len(object.getText().split()) > 25:
         text += ' [...]'
     return text