update get pipeline param names to id for consistency

plugins/ingest/src/test/resources/rest-api-spec/api/ingest.get_pipeline.json

@@ -3,10 +3,10 @@
     "documentation": "https://www.elastic.co/guide/en/elasticsearch/plugins/master/ingest.html",
     "methods": [ "GET" ],
     "url": {
-      "path": "/_ingest/pipeline/{ids}",
-      "paths": [ "/_ingest/pipeline/{ids}" ],
+      "path": "/_ingest/pipeline/{id}",
+      "paths": [ "/_ingest/pipeline/{id}" ],
       "parts": {
-        "ids": {
+        "id": {
           "type" : "string",
           "description" : "Comma separated list of pipeline ids. Wildcards supported",
           "required" : true

plugins/ingest/src/test/resources/rest-api-spec/test/ingest/20_crud.yaml

@@ -32,7 +32,7 @@
 
   - do:
       ingest.get_pipeline:
-        ids: "my_pipeline"
+        id: "my_pipeline"
   - match: { my_pipeline._source.description: "_description" }
   - match: { my_pipeline._version: 1 }
 
@@ -53,7 +53,7 @@
   - do:
       catch: missing
       ingest.get_pipeline:
-        ids: "my_pipeline"
+        id: "my_pipeline"
 
 ---
 "Test invalid config":