Avoid to repeat namespace querying on project milestone

app/controllers/projects/milestones_controller.rb

@@ -45,6 +45,7 @@ class Projects::MilestonesController < Projects::ApplicationController
   end
 
   def show
+    @project_namespace = @project.namespace.becomes(Namespace)
   end
 
   def create

app/views/shared/milestones/_issuable.html.haml

@@ -18,7 +18,7 @@
       = confidential_icon(issuable)
     = link_to issuable.title, issuable_url_args, title: issuable.title
   .issuable-detail
-    = link_to [project.namespace.becomes(Namespace), project, issuable] do
+    = link_to [namespace, project, issuable] do
       %span.issuable-number= issuable.to_reference
 
     - issuable.labels.each do |label|