search: fix broken collection redirect
search: fix broken collection redirect

* FIX Generates correct url for `/collection` redirect.

Signed-off-by: Jiri Kuncar <2bdffcb416fed3002465740d19a053a39918cbe5@cern.ch>

tiborsimko/invenio-search,inveniosoftware/invenio-search,inveniosoftware/invenio-search,tiborsimko/invenio-search