Added a indices flush to the rolling upgrades rest tests to ensure

they are on disk for the upgraded nodes to pick up.

qa/rolling-upgrade/build.gradle

@@ -39,7 +39,7 @@ task mixedClusterTest(type: RestIntegTestTask) {
     distribution = 'zip'
     clusterName = 'rolling-upgrade'
     unicastTransportUri = { seedNode, node, ant -> oldClusterTest.nodes.get(0).transportUri() }
-    dataDir = "${-> oldClusterTest.nodes[1].getDataDir()}"
+    dataDir = "${-> oldClusterTest.nodes[1].dataDir}"
   }
   systemProperty 'tests.rest.suite', 'mixed_cluster'
 
@@ -51,7 +51,7 @@ task upgradedClusterTest(type: RestIntegTestTask) {
     distribution = 'zip'
     clusterName = 'rolling-upgrade'
     unicastTransportUri = { seedNode, node, ant -> mixedClusterTest.nodes.get(0).transportUri() }
-    dataDir = "${-> oldClusterTest.nodes[0].getDataDir()}"
+    dataDir = "${-> oldClusterTest.nodes[0].dataDir}"
   }
   systemProperty 'tests.rest.suite', 'upgraded_cluster'
 }

qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/10_basic.yaml

@@ -21,6 +21,10 @@
           - '{"index": {"_index": "test_index", "_type": "test_type"}}'
           - '{"f1": "v5_mixed", "f2": 9}'
 
+ - do:
+     indices.flush:
+        index: test_index
+
  - do:
      search:
         index: test_index

qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/10_basic.yaml

@@ -15,6 +15,10 @@
           - '{"index": {"_index": "test_index", "_type": "test_type"}}'
           - '{"f1": "v5_old", "f2": 4}'
 
+ - do:
+     indices.flush:
+        index: test_index
+
  - do:
      search:
         index: test_index

qa/rolling-upgrade/src/test/resources/rest-api-spec/test/upgraded_cluster/10_basic.yaml

@@ -21,6 +21,10 @@
           - '{"index": {"_index": "test_index", "_type": "test_type"}}'
           - '{"f1": "v5_upgraded", "f2": 14}'
 
+ - do:
+     indices.flush:
+        index: test_index
+
  - do:
      search:
         index: test_index