defaults: remove elasticsearch.url

[ze42]

Not supported anymore on ES 7.x+

[myii]

@ze42 Just general feedback. Please also consider what needs to be done with the following lines:

kibana-formula/kibana/files/kibana-4.5-reference-config.yml

Lines 14 to 15 in c2b8c2c

	# The Elasticsearch instance to use for all your queries.
	# elasticsearch.url: "http://localhost:9200"

kibana-formula/pillar.example

Lines 6 to 7 in c2b8c2c

	config:
	elasticsearch.url: "http://localhost:9200"

[ze42]

@ze42 Just general feedback. Please also consider what needs to be done with the following lines:

First might be updated to specify it is about ES5?
mmm... 2nd might be kept as an example, as it uses es 5.

But yeah, it could probably benefit from having example that would match a more recent version of ES... not sure I'm in best position to do that, not having much idea how it works to start with