Fixed refresh button on history page (fix from rails_admin pull request: railsadminteam/rails_admin#2890)

Author: tomregelink

app/views/rails_admin/main/history.html.haml

@@ -15,7 +15,7 @@
     .input-group
       %input.form-control.input-small{name: "query", type: "search", value: query, placeholder: "#{t("admin.misc.filter")}", class: 'input-small'}
       %span.input-group-btn
-        %button.btn.btn-primary{type: "submit", :'data-disable-with' => "<i class='icon-white icon-refresh'></i> ".html_safe + t("admin.misc.refresh")}
+        %button.btn.btn-primary{type: 'submit', :'data-disable-with' => '<i class="icon-white icon-refresh"></i> '.html_safe + t('admin.misc.refresh')}
           %i.icon-white.icon-refresh
           = t("admin.misc.refresh")
 %table#history.table.table-striped.table-condensed