Fix sidebar title

Fix fixture

app/views/layouts/nav/sidebar/_project.html.haml

@@ -191,9 +191,9 @@
 
             - if project_nav_tab? :clusters
               = nav_link(controller: :clusters) do
-                = link_to project_clusters_path(@project), title: 'Clusters', class: 'shortcuts-clusters' do
+                = link_to project_clusters_path(@project), title: 'Cluster', class: 'shortcuts-cluster' do
                   %span
-                    Clusters
+                    Cluster
 
       - if project_nav_tab? :wiki
         = nav_link(controller: :wikis) do

spec/javascripts/fixtures/clusters.rb

@@ -11,7 +11,7 @@ describe Projects::ClustersController, '(JavaScript fixtures)', type: :controlle
   render_views
 
   before(:all) do
-    clean_frontend_fixtures('branches/')
+    clean_frontend_fixtures('clusters/')
   end
 
   before do