MDL-56576 admin: Cannot edit blocks on search page

Admin search page was processing the blocks delete request before the blocks
could process it.

Added a hidden field to the search results form so it can be sure the form submission
was for saving admin settings.

admin/templates/settings_search_results.mustache

@@ -37,6 +37,7 @@
 <form action="{{actionurl}}" method="post" id="adminsettings">
     <div>
         <input type="hidden" name="sesskey" value="{{sesskey}}">
+        <input type="hidden" name="action" value="save-settings">
     </div>
     <fieldset>
         <div class="clearer"></div>