Simplify Init for Elasticsearch

Perform reindex operation for all indexes on init for elasticsearch
index. This change allows for starting an elasticsearch index with only
the init command, similar to a Lucene index.

Remove reindex operation on ElasticReindexIT, since with this change
performing a reindex manually is no longer needed.

Test plan: Run InitIT, ElasticReindexIT and ReindexIT.

Feature: Issue 12704
Change-Id: If7741771e25a6063c5116ab2bce39fbe0e0ea93b