Bug 24813: Prevent api/v1/holds.t to fail randomly

Bug 24813: Prevent api/v1/holds.t to fail randomly

Hold cannot be suspended if found=W:
Koha::Hold->suspend_hold
 90     if ( $self->is_found ) {    # We can't suspend found holds

So when TestBuilder generate a hold with found=W the test fail.

A question however:
Why did not we have the correct exception displayed somewhere? That
would be much more helpful to find the problem!

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