we currently don't expose this.
This adds the following to the OS section of `_nodes`:
```
"os": {
"name": "Mac OS X",
...
}
```
and the following to the OS section of `_cluster/stats`:
```
"os": {
...
"names": [
{
"name": "Mac OS X",
"count": 1
}
],
...
},
```
Closes#11807
Also changes the response format of that section to:
```
"open_file_descriptors": {
"min": 200,
"max": 346,
"avg": 273
}
```
Closes#4681
Note: this is an aggregate of 3 commits in the 0.90 branch
Andrey Fadeyev
Boaz Leskes
Martijn van Groningen
spapin
Clinton Gormley
Patrik Ragnarsson