Bug 27633: (bug 15436 follow-up) Fix duplicate of 440$v at the OPAC

Bug 27633: (bug 15436 follow-up) Fix duplicate of 440$v at the OPAC

Only display a in link, not v that is displayed later.

It has been fixed in different other places by
  commit 81f71d45fe4fee92596ea8d8edb57c602490e9b1
  Bug 15436: Use semicolon between series name and volume

but missed one occurrence.

Test plan:
Add a 440$a and $v and confirm that the display at the OPAC is now the
same as the staff interface.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>