use plone.base and remove dependencies to CMFPlone

plone/app/discussion/catalog.py

@@ -6,10 +6,10 @@ Also provide event handlers to actually catalog the comments.
 from DateTime import DateTime
 from plone.app.discussion.interfaces import IComment
 from plone.app.discussion.interfaces import IConversation
+from plone.base.utils import safe_text
 from plone.indexer import indexer
 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
 
 
@@ -72,7 +72,7 @@ def title(object):
 def creator(object):
     if not object.creator:
         return
-    value = safe_unicode(object.creator)
+    value = safe_text(object.creator)
     return value