Products.CMFActivity: Inverse dequeueMessage return value

dequeueMessage used to return False when something was done, and True
otherwise. The only caller which uses that value then reverses it, causing
a double-negative which makes the code confusing to read.
Inverse the meaning of the return value, getting rid of this double-
negation.

bt5/erp5_core_test/TestTemplateItem/portal_components/test.erp5.testERP5Catalog.py

@@ -351,7 +351,7 @@ class TestERP5Catalog(ERP5TypeTestCase, LogInterceptor):
       # XXX: duplicate ActivityTool.tic, without locking as we are being
       # multiple activity nodes in a single process.
       for activity in ActivityTool.activity_dict.itervalues():
-        while not activity.dequeueMessage(activity_tool, node_id, ()):
+        while activity.dequeueMessage(activity_tool, node_id, ()):
           pass
     # Monkey-patch catalog to synchronise between main thread and the
     # isolated transaction.

product/CMFActivity/Activity/SQLBase.py

@@ -1038,7 +1038,7 @@ CREATE TABLE %s (
       self.finalizeMessageExecution(activity_tool, message_list,
                                     uid_to_duplicate_uid_list_dict)
     transaction.commit()
-    return not message_list
+    return bool(message_list)
 
   def deleteMessageList(self, db, uid_list):
     db.query("DELETE FROM %s WHERE uid IN (%s)" % (

product/CMFActivity/ActivityTool.py

@@ -1387,7 +1387,7 @@ class ActivityTool (BaseTool):
             activity_list.sort(key=sort_key) # stable sort
             for i, activity in enumerate(activity_list):
               # Transaction processing is the responsability of the activity
-              if not activity.dequeueMessage(inner_self, processing_node,
+              if activity.dequeueMessage(inner_self, processing_node,
                 node_family_id_set):
                 activity_list.append(activity_list.pop(i))
                 break