slack: make selected events default to off

rhodecode/integrations/types/slack.py

@@ -146,7 +146,7 b' class SlackIntegrationType(IntegrationTy'
             widget='checkbox_list',
             choices=sorted([e.name for e in cls.valid_events]),
             description="Events activated for this integration",
-            default=[e.name for e in cls.valid_events],
+            # default=[e.name for e in cls.valid_events],
             name='events'
         ))
         return schema