Reduce the amount of JavaScript written in views

Seeing `:javascript` all over Views feels like a code smell. This goes a
long way towards reducing the amount of JS in views, but there's still
plenty to be done on that front.

app/views/refs/_head.html.haml

@@ -1,7 +1,7 @@
 %ul.nav.nav-tabs
   %li
     = form_tag switch_project_refs_path(@project), method: :get, class: "project-refs-form", remote: true do
-      = select_tag "ref", grouped_options_refs, onchange: "$(this.form).trigger('submit');", class: "project-refs-select"
+      = select_tag "ref", grouped_options_refs, onchange: "$(this.form).trigger('submit');", class: "project-refs-select chosen"
       = hidden_field_tag :destination, "tree"
       = hidden_field_tag :path, params[:path]
   %li{class: "#{'active' if (controller.controller_name == "refs") }"}

app/views/refs/_tree.html.haml

@@ -47,10 +47,7 @@
 
 :javascript
   $(function(){
-    $('.project-refs-select').chosen();
-
     history.pushState({ path: this.path }, '', "#{@history_path}");
-
   });
 
   // Load last commit log for each file in tree

app/views/refs/blame.html.haml

@@ -38,8 +38,3 @@
               = preserve do
                 %pre
                   = Gitlab::Encode.utf8 lines.join("\n")
-
-:javascript
-  $(function(){
-    $('.project-refs-select').chosen();
-  });