6584: Enable searching on Zebra's Bib-level index

6584: Enable searching on Zebra's Bib-level index

Bib-level is already indexed in MARC21 record.abs.
But you cannot search this index, because it is commented in ccl.properties and
not listed in getIndexes of Search.pm.
This very simple patch does only do those two things.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
(cherry picked from commit f02796d989a377266a844e5b498945372a2a254f)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>