ReIndex API does not always update the schema mapping to ElasticSearch

When an augmenter configuration is deployed, in order to make use of the updated configuration, two operations are required:

1. Update the schema mapping with extended schema from the augmenter configuration to ElasticSearch
2. Re-index the records of the affected kind. In this scenario, it is expected that users still can search the "old" data before the re-index is completed.

Current implementation of ReIndex API does not always update the schema mapping to ElasticSearch if the forceClean option is not set to true. However, when the forceClean option is set to true, the original index will be deleted/purged. In this case, users may not be able to search the expected data before a new index is fully populated.