Bug 12060: remove extraneous tags from header.inc

By correcting the indentation, it became more apparent the two
markup errors (stray </li> and </div> tags) that were generated
by pasting the page source of
   PROTOCOL://STAFFCLIENT/cgi-bin/koha/tools/holidays.pl
into http://validator.w3.org/check

TEST PLAN
---------
1) Home -> Tools -> Calendar in the staff client
2) In another tab open http://validator.w3.org/check
3) Select Validate by Direct Input
4) In the staff client, view the page source
5) Copy the page source to the Validation text box in the
    other tab.
6) Click the 'Check' button.
   -- There will be 3 errors.
7) Apply the patch.
8) Refresh the staff client page.
9) Copy the revised page source into the validation text box.
10) click the 'Check' button.
    -- There will be 1 error.
11) Run the koha qa test tool.

NOTE: This error is not in the intended file to fix.
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
git diff --color -w HEAD^ reveals, that only a </li> and a </div>
are removed by this patch, all other changes are whitespace.
Passes all tests and QA script.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
(cherry picked from commit 7382bee7cdcf289487dd8770add5412b7d44d11e)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>