Remove no longer required class.

app/views/projects/milestones/show.html.haml

@@ -63,7 +63,7 @@
       %span.time-elapsed
         %strong== #{@milestone.percent_time_used}%
         time elapsed
-    %span.pull-right.tab-issues-buttons.tab-labels-buttons
+    %span.pull-right.tab-issues-buttons
       - if can?(current_user, :create_issue, @project)
         = link_to new_namespace_project_issue_path(@project.namespace, @project, issue: { milestone_id: @milestone.id }), class: "btn  btn-grouped", title: "New Issue" do
           %i.fa.fa-plus