[TEST] Disable automatic refresh to prevent unintended field data warming of the the _parent field.
[TEST] Only use the clients from the node.
Also send Refresh and Flush actions to relocation targets

Currently we send relocation & flush actions based on all assigned ShardRoutings. During the final stage of relocation, we may miss to refresh/flush a shard if the coordinating node has not yet processed the cluster state update indicating that a relocation is completed *and* the relocation target node has already processed it (i.e., started the shard and has accepted new indexing requests).

Closes #6545
Fixed typo in TransportAction log line
[TEST] Remove indentation on indices.stats test setups

The new indices.stats tests have the setup section indented, which
can cause problems for some yaml parsers.
significant terms: fix json response

Commit fbd7c9aa5d6c1c introduced a regression that caused
the min_doc_count to be equal to the number of documents in the
background set. As a result no buckets were built when the
response for significant terms was created.
This only affected the final XContent response.

closes #6535
[DOCS] Fixed json example in nested-aggregation.asciidoc