[FIX] rating_*: domain on m2o for rating mail template

Rating is implemented for project.issue, but it is
impossible to set a template on the stage since the
domain force the mail.template to be declared on
project.task.

We use the same mecanism as `mail_template_id`
declared on project.stage.task in project
module. The list of available template on the stage
form view will be the ones for issue and task like
mail_template_id.

addons/rating_project/models/project.py

@@ -7,10 +7,13 @@ class ProjectTaskType(models.Model):
 
     _inherit = 'project.task.type'
 
+    def _default_domain_rating_template_id(self):
+        return [('model', '=', 'project.task')]
+
     rating_template_id = fields.Many2one(
         'mail.template',
         string='Rating Email Template',
-        domain=[('model', '=', 'project.task')],
+        domain=lambda self: self._default_domain_rating_template_id(),
         help="Select an email template. An email will be sent to the customer when the task reach this step.")
     auto_validation_kanban_state = fields.Boolean('Automatic kanban status', default=False,
         help="Automatically modify the kanban state when the customer reply to the feedback for this stage.\n"

addons/rating_project_issue/models/project_issue.py

@@ -25,6 +25,16 @@ class ProjectIssue(models.Model):
         return super(ProjectIssue, self).rating_apply(rate, token=token, feedback=feedback, subtype="rating_project_issue.mt_issue_rating")
 
 
+
+class Stage(models.Model):
+
+    _inherit = ['project.task.type']
+
+    def _default_domain_rating_template_id(self):
+        domain = super(Stage, self)._default_domain_rating_template_id()
+        return ['|'] + domain + [('model', '=', 'project.issue')]
+
+
 class Project(models.Model):
 
     _inherit = "project.project"