Remove tree_action keyword

tree_action is removed since version 2.0 with the merge of tree and list view.

doc/topics/actions.rst

@@ -22,12 +22,10 @@ Keyword
 
 Keywords define where to display the action in the client.
 
-There are six places:
+There are five places:
 
     * Open tree (`tree_open`)
 
-    * Action tree (`tree_action`)
-
     * Print form (`form_print`)
 
     * Action form (`form_action`)

trytond/ir/action.py

@@ -102,7 +102,6 @@ class ActionKeyword(ModelSQL, ModelView):
     __name__ = 'ir.action.keyword'
     keyword = fields.Selection([
             ('tree_open', 'Open tree'),
-            ('tree_action', 'Action tree'),
             ('form_print', 'Print form'),
             ('form_action', 'Action form'),
             ('form_relate', 'Form relate'),