Bug 23670: Load Koha::Exceptions::ElasticSearch module in Koha::SearchEngine::Elastic...

Bug 23670: Load Koha::Exceptions::ElasticSearch module in Koha::SearchEngine::Elasticsearch

Prevent Koha::SearchEngine::Elasticsearch from dying when trying to run
Koha::Exceptions::Elasticsearch::MARCFieldExprParseError->throw()

Plan test:

1. Go to Administration -> Searchengine configuration, and add a mapping
   for 995Z, whatever the search field (I did it with local-classification),
   save
2. run $KOHA_PATH/misc/search_tools/rebuild_elasticsearch.pl -v -d -b
3. see it die asking for Koha::Exceptions::Elasticsearch
4. apply patch
5. rerun $KOHA_PATH/misc/search_tools/rebuild_elasticsearch.pl -v -d -b
6. see it throw: Invalid MARC field expression: 995Z

Signed-off-by: Séverine QUEUNE <severine.queune@bulac.fr>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>