Bug 12441: Search.pl conditional checks and displays using same syspref

Bug 12441: Search.pl conditional checks and displays using same syspref

Script search.pl checks OPACdefaultSortField and OPACdefaultSortOrder, but
shows defaultSortField and defaultSortOrder when using Advanced Search
in the staff client.

Test plan:
Apply the patch and then check that the Advanced Search uses
defaultSortOrder and defaultSortField sysprefs instead of the OPAC
sysprefs in the conditional. Check that sort behaviour in Advanced
Search still functions as expected. (It should do - this doesn't change
what displays, just improves consistency).

Sponsored-by: Catalyst IT
Signed-off-by: Michal Denar <black23@gmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>