Bug 21962: Fix authority search using 'all'

Bug 21962: Fix authority search using 'all'

To test:
1 - Set search engine to Zebra
2 - Have some authorities and indexes up to date
3 - Search authorities with option 'search entire record'
4 - No results
5 - Apply patch
6 - Run unit tests, they pass!
7 - Repeat search
8 - Results!

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>