ActivityTool: Do not mark as non-indexable.

portal_activities contains documents which need to be (and are) indexed.
For consistency, the tool itself should be indexable.

product/CMFActivity/ActivityTool.py

@@ -628,8 +628,6 @@ class ActivityTool (Folder, UniqueObject):
     allowed_types = ( 'CMF Active Process', )
     security = ClassSecurityInfo()
 
-    isIndexable = False
-
     manage_options = tuple(
                      [ { 'label' : 'Overview', 'action' : 'manage_overview' }
                      , { 'label' : 'Activities', 'action' : 'manageActivities' }