Handle search timeouts more gracefully

Handle search timeouts more gracefully

Another tweak courtesy of berick

Returns 0 results if open-ils.storage timeouts instead of a nasty uncaught
undefined ARRAY exception resulting in an OPAC "spinning wheel of death"
(formerly the "green knight rider bar of death".

Note that in the event of storage timeouts, you should tune and/or beef-up
your database.

Signed-off-by: Jason Etheridge <jason@esilibrary.com>