[ILM] fix ilm.remove_policy rest-spec
The rest interface for remove-policy-from-index API does not support
`_ilm/remove`, it requires that an `{index}` pattern be defined in
the URL path. This fixes the rest-api-spec to reflect the implementation
"methods": [ "POST" ],
"url": {
"path": "/{index}/_ilm/remove",
- "paths": ["/{index}/_ilm/remove", "/_ilm/remove"],
+ "paths": ["/{index}/_ilm/remove"],
"parts": {
"index": {
"type" : "string",
