[Elasticsearch plugin] Newly-created products not correctly indexed

[michaelbromley]

Describe the bug
When creating a new product, it does not get indexed by Elasticsearch.

To Reproduce
Steps to reproduce the behavior:

1. Configure the server to use the ElasticsearchPlugin
2. Create a new product with a single variant and save
3. Observe the error in server logs:

[run:worker] error 8/26/19, 13:05 - [ElasticsearchPlugin] Some errors occurred running bulk operations on variant-index-item! Set logger to "debug" to print all errors.
[run:worker] debug 8/26/19, 13:05 - [ElasticsearchPlugin] {
[run:worker]   "type": "document_missing_exception",
[run:worker]   "reason": "[variant-index-item][9832]: document missing",
[run:worker]   "index_uuid": "dReGwzY8RgOntwpvi1HIgg",
[run:worker]   "shard": "0",
[run:worker]   "index": "vendure-variants"
[run:worker] }

Environment (please complete the following information):

• @vendure/core version: 0.1.2-beta.12

[michaelbromley]

This is caused by a race condition where the Variants do not yet exist upon product creation.