[REF] mail: clean some JS code

1. Removed `getLocalMessages` method in mailbox, and replaced
   with an override on `getMessages`.

   (This method was used before the distinction was made
   between `getMessages` and `fetchMessages`)

2. Removed unused method `_warnUpdatedUnreadCounter` in
   abstract thread window.

   (Leftover from an early POC)

3. Set the default value `''` for the status of a thread.

   (The method `getStatus` should always return a string)

4. Enforce default value `false` for detached status of channel.

   (The method `isDetached` should always return a boolean)

5. Improve readability of some tests.

   (removed useless variables and/or redundant code)

1 files changed, 0 insertions, 7 deletions

diff --git a/addons/mail/static/src/js/thread_windows/abstract_thread_window.js b/addons/mail/static/src/js/thread_windows/abstract_thread_window.js
index eb8a7da3634..8a8bf3a0077 100644
--- a/addons/mail/static/src/js/thread_windows/abstract_thread_window.js
+++ b/addons/mail/static/src/js/thread_windows/abstract_thread_window.js
@@ -384,13 +384,6 @@ var AbstractThreadWindow = Widget.extend({
             this.updateVisualFoldState();
         }
     },
-    /**
-     * Warn other mail components that the unread counter has been updated
-     *
-     * @abstract
-     * @private
-     */
-    _warnUpdatedUnreadCounter: function () {},
 
     //--------------------------------------------------------------------------
     // Handlers