Bug 7338 Links on Serial Collection page

Bug 7338 Links on Serial Collection page

Don't display link to the serial, when the collection page displays just
one subscription. Display it when several subscriptions. Alway display a
link for displaying biblio record other subscriptions.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Patch works nicely, but always shows link to 'any subscriptions'.
I did a follow-up so the link would only show if there was more
than 1 subscription for the record.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>