Bug 18897: Koha_Elasticsearch_Indexer.t doesn't skip when ES module(s) not installed

Bug 18897: Koha_Elasticsearch_Indexer.t doesn't skip when ES module(s) not installed

If Catmandu::Importer::MARC is not installed,
Koha_Elasticsearch_Indexer.t fails instead of skipping.
It should skip as ES is not currently mandatory.

Test Plan:
1. Run "prove t/db_dependent/Koha_Elasticsearch_Indexer.t"
   as koha-shell
2. Note failure on test 1/5 indicating module not installed.
3. Apply patch.
4. Re-run "prove t/db_dependent/Koha_Elasticsearch_Indexer.t"
5. Note test now skips.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Lee Jamison <ldjamison@marywood.edu>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit b6b6acf285f98a7da665eac6741cdfc87b089b57)
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>