Bug 15960: Use Font Awesome icons for classification filing rule deletion error

When deletion of a classification filing rule is impossible, the dialog
saying so should be styled with Font Awesome icons. This patch corrects
this omission from the patch for Bug 15785.

Also changed: The dialog is now an "alert" style dialog instead of a
"message" one.

To test, apply the patch and go to Administration -> Classification
sources.

- Locate a classification filing rule which is in use by a
  classification source.
- Click the "Delete" link for that rule and verify that the resulting
  dialog is correctly styled.
- Click the "OK" button and confirm that you are correctly redirected.

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Works as advertise

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com

koha-tmpl/intranet-tmpl/prog/en/modules/admin/classsources.tt

@@ -216,12 +216,12 @@ function CheckRuleForm(f) {
 [% END %]
 
 [% IF ( delete_sort_rule_impossible ) %]
-<div class="dialog message"><h3>Cannot delete filing rule <span class="ex">'[% sort_rule %]'</span></h3>
+<div class="dialog alert"><h3>Cannot delete filing rule <span class="ex">'[% sort_rule %]'</span></h3>
     <p>The filing rule [% sort_rule %] is used by at least one classification source.  Please
     remove it from all classification source definitions before trying again.
     </p>
     <form action="[% script_name %]" method="get">
-        <input type="submit" value="OK" class="approve" />
+          <button type="submit" class="approve"><i class="fa fa-fw fa-check"></i> OK</button>
     </form>
 </div>
 [% END %]