Graph: Moved the index creation to a `setup` section in the REST test

Closes elastic/elasticsearch#2679

Original commit: elastic/x-pack-elasticsearch@51a4a5e530

elasticsearch/x-pack/graph/src/test/resources/rest-api-spec/test/graph/10_basic.yaml

@@ -1,19 +1,21 @@
 ---
-"Test basic graph explore":
+setup:
-  - do:
+- do:
     indices.create:
       index: test_1
       body:
         settings:
           index:
-             number_of_replicas: 0
             number_of_shards:   1
+            number_of_replicas: 0
         mappings:
           test:
             properties:
               keys:
-                 type : "integer"
+                type : integer
 
+---
+"Test basic graph explore":
   - do:
       index:
           index:  test_1