REST spec: Added missing query_cache param to clear_cache, nodes.stats and indices.stats

Relates to #7167 and #7161

rest-api-spec/api/indices.clear_cache.json

@@ -65,6 +65,10 @@
         "recycler": {
           "type" : "boolean",
           "description" : "Clear the recycler cache"
+        },
+        "query_cache": {
+          "type" : "boolean",
+          "description" : "Clear query cache"
         }
       }
     },

rest-api-spec/api/indices.stats.json

@@ -17,7 +17,7 @@
         },
         "metric" : {
           "type" : "list",
-          "options" : ["_all", "completion", "docs", "fielddata", "filter_cache", "flush", "get", "id_cache", "indexing", "merge", "percolate", "refresh", "search", "segments", "store", "warmer", "suggest"],
+          "options" : ["_all", "completion", "docs", "fielddata", "filter_cache", "flush", "get", "id_cache", "indexing", "merge", "percolate", "query_cache", "refresh", "search", "segments", "store", "warmer", "suggest"],
           "description" : "Limit the information returned the specific metrics."
         }
       },

rest-api-spec/api/nodes.stats.json

@@ -20,7 +20,7 @@
         },
         "index_metric" : {
           "type" : "list",
-          "options" : ["_all", "completion", "docs", "fielddata", "filter_cache", "flush", "get", "id_cache", "indexing", "merge", "percolate", "refresh", "search", "segments", "store", "warmer", "suggest"],
+          "options" : ["_all", "completion", "docs", "fielddata", "filter_cache", "flush", "get", "id_cache", "indexing", "merge", "percolate", "query_cache", "refresh", "search", "segments", "store", "warmer", "suggest"],
           "description" : "Limit the information returned for `indices` metric to the specific index metrics. Isn't used if `indices` (or `all`) metric isn't specified."
         },
         "node_id": {