Message Title

Of one starts Hibernate Search without the Elasticsearch cluster being reachable, we get something like this:
2019-06-17 10:34:42,919 ERROR [org.hib.sea.eng.rep.imp.RootFailureCollector] (main) HSEARCH000521: Hibernate Search bootstrap encountered a non-fatal failure; continuing bootstrap for now to list all mapping problems, but the bootstrap process will ultimately be aborted.
Context: backend '_quarkus_'
Failure:: org.hibernate.search.util.common.SearchException: HSEARCH400080: Failed to detect the Elasticsearch version running on the cluster.
    at org.hibernate.search.backend.elasticsearch.client.impl.ElasticsearchClientUtils.getElasticsearchVersion(ElasticsearchClientUtils.java:72)
    at org.hibernate.search.backend.elasticsearch.impl.ElasticsearchLinkImpl.onStart(ElasticsearchLinkImpl.java:92)
    at org.hibernate.search.backend.elasticsearch.impl.ElasticsearchBackendImpl.start(ElasticsearchBackendImpl.java:131)
    at org.hibernate.search.engine.common.impl.BackendPartialBuildState.finalizeBuild(BackendPartialBuildState.java:41)
    at org.hibernate.search.engine.common.impl.SearchIntegrationPartialBuildStateImpl.finalizeIntegration(SearchIntegrationPartialBuildStateImpl.java:99)
    at org.hibernate.search.mapper.orm.bootstrap.impl.HibernateOrmIntegrationBooterImpl.doBootSecondPhase(HibernateOrmIntegrationBooterImpl.java:241)
    at org.hibernate.search.mapper.orm.bootstrap.impl.HibernateOrmIntegrationBooterImpl.bootNow(HibernateOrmIntegrationBooterImpl.java:165)
....
Caused by: org.hibernate.search.util.common.SearchException: HSEARCH400007: Elasticsearch request failed.
Request: GET with parameters {}
Response: null
at org.hibernate.search.backend.elasticsearch.client.impl.ElasticsearchClientUtils.getElasticsearchVersion(ElasticsearchClientUtils.java:68)
...
Caused by: [...] Connection refused