Omit link to generate labels if user does not have access to create them

Closes https://github.com/gitlabhq/gitlabhq/issues/8353

CHANGELOG

 Please view this file on the master branch, on stable branches it's out of date.
 
 v 7.12.0 (unreleased)
+  - Omit link to generate labels if user does not have access to create them (Stan Hu)
   - Disable changing of the source branch in merge request update API (Stan Hu)
   - Shorten merge request WIP text.
   - Add option to disallow users from registering any application to use GitLab as an OAuth provider

app/views/projects/labels/index.html.haml

@@ -13,4 +13,7 @@
     = paginate @labels, theme: 'gitlab'
   - else
     .light-well
+      - if can? current_user, :admin_label, @project
         .nothing-here-block Create first label or #{link_to 'generate', generate_namespace_project_labels_path(@project.namespace, @project), method: :post} default set of labels
+      - else
+        .nothing-here-block No labels created