In order to be consistent (and because in 1.0 we switched from
parameter driven information to specifzing the metrics as part of the URI)
this patch moves from 'plugin' to 'plugins' in the Nodes Info API.
- Removed "ok": true from response examples
- Added "created" flag to index response examples
- Replaced exists flag with found in delete response examples
Important: This breaks backwards compatibility with 0.90
* Removed endpoints: /_cluster/nodes, /_cluster/nodes/nodeId1,nodeId2
* Disallow usage of parameters, but make required metrics part of URI
* Changed NodesInfoRequest to return everything by default
* Fixed NPE in NodesInfoResponse
Closes#4055
Costin Leau
Alexander Reelsen
Luca Cavanna
Clinton Gormley