Bug 24213: Fix Koha::Object->get_from_storage if the object has been deleted

Without this patch it fails with something like:
  DBIC result _type  isn't of the _type Subscription at t/db_dependent/Biblio.t line 627.

Test plan:
- Apply the first patch (Add tests)
- Confirm that they fail
- Apply this patch
- Confirm that the tests pass

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>

Signed-off-by: Joy Nelson <joy@bywatersolutions.com>
(cherry picked from commit a27c5c9dcd)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit f79f4dc5b1)

Signed-off-by: Hayley Mapley <hayleymapley@catalyst.net.nz>

Koha/Object.pm

@@ -263,6 +263,7 @@ sub unblessed {
 sub get_from_storage {
     my ( $self, $attrs ) = @_;
     my $stored_object = $self->_result->get_from_storage($attrs);
+    return unless $stored_object;
     my $object_class  = Koha::Object::_get_object_class( $self->_result->result_class );
     return $object_class->_new_from_dbic($stored_object);
 }