[ADD] uninstall_hook to remove done activities

mail_activity_done/__init__.py

@@ -1,2 +1,2 @@
 from . import models
-from .hooks import post_load_hook, pre_init_hook
+from .hooks import post_load_hook, pre_init_hook, uninstall_hook

mail_activity_done/__manifest__.py

@@ -16,5 +16,5 @@
     ],
     "pre_init_hook": "pre_init_hook",
     "post_load": "post_load_hook",
-
+    'uninstall_hook': 'uninstall_hook',
 }

mail_activity_done/hooks.py

@@ -52,3 +52,15 @@ def post_load_hook():
     if not hasattr(MailActivity, 'action_feedback_original'):
         MailActivity.action_feedback_original = MailActivity.action_feedback
         MailActivity.action_feedback = new_action_feedback
+
+
+def uninstall_hook(cr, registry):
+    """ The objective of this hook is to remove all activities that are done
+        upon module uninstall
+        """
+    cr.execute(
+        """
+        DELETE FROM mail_activity
+        WHERE done=True
+        """
+    )