Bug 36879: Spurious warning in QueryBuilder

Bug 36879: Spurious warning in QueryBuilder

Test plan:

With ElasticSearch enabled,
* Perform a search using the default  sort order
  (i.e. 'relevance').
* Verify that no warnings are generated in
  plack-intranet-error.log

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: wainuiwitikapark <wainuiwitikapark@catalyst.net.nz>
(cherry picked from commit 85ae71cfd4226a5af93f5650aae6ced34f1b8136)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>