Bug 9857 - Follow-up - Fix for searches with su= or su:

Bug 9857 - Follow-up - Fix for searches with su= or su:

When the initial search is su=.../su:... the links was
not constructed correctly. With this change, it should
be the case.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit 786deba62beb5a52a543af5415610e14f7d0a8c5)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
(cherry picked from commit 112116e45f4676aea3a63faa42b0e6a3e2456706)
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>