Use font awesome instead of Unicode. Feedback from:

https://gitlab.com/gitlab-org/gitlab-ce/commit/53121601f38155e926eed300160f79dd4bc0768b#note_12465224

app/views/projects/runners/_runner.html.haml

@@ -5,7 +5,8 @@
       - if @runners.include?(runner)
         = link_to runner.short_sha, runner_path(runner)
         - if runner.locked?
-          %small{title: 'Exclusive to this project'} 🔒
+          %small{title: 'Exclusive to this project'}
+            = icon('lock')
         %small
           = link_to edit_namespace_project_runner_path(@project.namespace, @project, runner) do
             %i.fa.fa-edit.btn