Bug 766: Remove CGI::scrollinglist from authorised_values.pl

Bug 766: Remove CGI::scrollinglist from authorised_values.pl

This patch removes the only instance in this file.
Also fixes array sorting, removes some tabs, removes
an unneeded $dbh handler (there is a global one).
Makes use of C4::Koha::GetAuthorisedValueCategories.

To test:
1. Apply the patch
2. Go to Administration > Authorised values
3. Replaced pulldown next to 'Show category' must
show all (present & system) categories correctly ordered.
4. Select some and check for regressions, e.g. CCODE, Bsort2, YES_NO
no changes must be observed

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Works as described, no problems found.
Passes tests and QA script.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>