Bug 11038: Enable use of IntranetUserCSS on staff client login page

Bug 11038: Enable use of IntranetUserCSS on staff client login page

This patch enable use of IntranetUserCss on staff client
login page.

To test:
1) Add something to IntranetUserCSS to modify login page,
for example

 #login h1 a {
   height:30px;
 }

2) Logout from staff client, no changes on login page.
3) Apply the patch
4) Reload, now logo is cut in half :)
Bonus) Login again an try changing image, add

 #login h1 {
  background: url(http://example.com/img/other-logo.png) no-repeat top center;
 }

and fix height. Logout and check

This also affects 3.20 and perhaps earlier versions.
Re-upload to fix examples

Works as expected.
Signed-off-by: Marc Véron <veron@veron.ch>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>