[FIX] mail: track date change

- Set your timezone in Brasil
- Install the Maintenance module
- Create a Maintenance Request, set the Requested Date to 2017-06-15
- Save

In the chatter, the track fields message shows a Requested Date of
2017-06-14.

This can actually happen with any date tracked. The issue comes from the
web client: it converts the date in UTC, which should of course not be
done. This only applies for a datetime, not for a date.

opw-746216

addons/mail/static/src/js/chat_manager.js

@@ -287,14 +287,22 @@ function make_message (data) {
     // can not be done in preprocess, since it alter the original value
     if (msg.tracking_value_ids && msg.tracking_value_ids.length) {
         _.each(msg.tracking_value_ids, function(f) {
-            if (_.contains(['date', 'datetime'], f.field_type)) {
-                var format = (f.field_type === 'date') ? 'LL' : 'LLL';
+            if (f.field_type === 'datetime') {
+                var format = 'LLL';
                 if (f.old_value) {
                     f.old_value = moment.utc(f.old_value).local().format(format);
                 }
                 if (f.new_value) {
                     f.new_value = moment.utc(f.new_value).local().format(format);
                 }
+            } else if (f.field_type === 'date') {
+                var format = 'LL';
+                if (f.old_value) {
+                    f.old_value = moment(f.old_value).local().format(format);
+                }
+                if (f.new_value) {
+                    f.new_value = moment(f.new_value).local().format(format);
+                }
             }
         });
     }