Bug 26314: Only display volumes link when required

Bug 26314: Only display volumes link when required

This patch makes C4::XSLT query for volumes the same way it would do
with the generated link (i.e. based on UseControlNumber) and passes
a flag to the XSLT so it displays (or not) the 'Show volumes' link.

To test:
1. Apply the first patch
2. Have a known record without volumes
3. Open the record in the OPAC
=> FAIL: It shows the 'Show volumes' link
4. Have a record known to have volumes
5. Open the record in the OPAC
=> SUCCESS: It shows the 'Show volumes' link
6. Apply this patch and restart_all
7. Reload the above records
=> SUCCESS: It shows the link where it has to, and hides it where it
   shouldn't be displayed.
8. Repeat for Intranet
9. Sign off :-D

Signed-off-by: Michaela Sieber <michaela.sieber@kit.edu>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>