Bug 20310: (follow-up) Check if biblio exists; 755 host_record.t

Bug 20310: (follow-up) Check if biblio exists; 755 host_record.t

In order to prevent an error like:
Can't call method "host_record" on an undefined value at opac/opac-request-article.pl

Also chmod's host_record.t to 755 (File must have the exec flag)

Test plan:
Change the URL so that the biblionumber does not exist.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>