Fix: recs without online_loc break results display

Fix: recs without online_loc break results display

Don't try to check a substring of rec.online_loc()[0] if there
are no entries returned by rec.online_loc() to begin with.

Manifests result_info_2 (with the prev/next links) not being
visible on the bottom of the search results page when there
are any bibs present in the results which have no online_loc()
entries.

Signed-off-by: Jeff Godin <jgodin@tadl.org>