Monitoring: Update REST/test namespace

Related to elastic/elasticsearch#1702

Original commit: elastic/x-pack-elasticsearch@6000fd4010

elasticsearch/x-pack/marvel/src/test/resources/rest-api-spec/api/xpack.monitoring.bulk.json

@@ -1,5 +1,5 @@
 {
-  "monitoring.bulk": {
+  "xpack.monitoring.bulk": {
     "documentation": "http://www.elastic.co/guide/en/marvel/current/appendix-api-bulk.html",
     "methods": ["POST", "PUT"],
     "url": {

elasticsearch/x-pack/marvel/src/test/resources/rest-api-spec/test/monitoring/bulk/10_basic.yaml

@@ -18,7 +18,7 @@ setup:
   - set: {version.number: version}
 
   - do:
-      monitoring.bulk:
+      xpack.monitoring.bulk:
         system_id:      "kibana"
         system_version: $version
         body:
@@ -52,7 +52,7 @@ setup:
   - match: { hits.total: 2 }
 
   - do:
-      monitoring.bulk:
+      xpack.monitoring.bulk:
         system_id:      "kibana"
         system_version: $version
         type: "default_type"