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: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 347291727dd63cdba508b84336bed4d12efee57d)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit ab51747dcc8b9a14d73e0efe4763937763f7f622)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>