Move Elasticsearch fixes from 2.15.1 to 2.15.2
Move Elasticsearch fixes from 2.15.1 to 2.15.2

Although there were a couple of Elasticsearch related fixes included
in 2.15.1, it doesn't make sense to mention them in the release notes
because Elasticsearch is still not yet fully working.

Move them to 2.15.2.

Change-Id: I9d3f750e1461e5edbcf431656097d54f4087ba30

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