Use warning for locked runners:

Feedback from:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/4961#note_12794221

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

@@ -5,7 +5,7 @@
     - else
       %span.label.label-info specific
     - if runner.locked?
-      %span.label.label-danger locked
+      %span.label.label-warning locked
     - unless runner.active?
       %span.label.label-danger paused
 

app/views/admin/runners/index.html.haml

@@ -40,7 +40,7 @@
           %span.label.label-info specific
           \- run builds from assigned projects
         %li
-          %span.label.label-danger locked
+          %span.label.label-warning locked
           \- runner cannot be assigned to other projects
         %li
           %span.label.label-danger paused