Tests: Adding additional debug info to upgrade test.

src/test/java/org/elasticsearch/rest/action/admin/indices/upgrade/UpgradeTest.java

@@ -115,9 +115,15 @@ public class UpgradeTest extends ElasticsearchBackwardsCompatIntegrationTest {
             indexRandom(true, builder);
             ensureGreen(indexName);
         }
+        logger.debug("--> Upgrading nodes");
+        logClusterState();
+        logSegmentsState(null);
         backwardsCluster().allowOnAllNodes(indexNames);
         backwardsCluster().upgradeAllNodes();
         ensureGreen();
+        logger.debug("--> Nodes upgrade complete");
+        logClusterState();
+        logSegmentsState(null);
         
         final HttpRequestBuilder httpClient = httpClient();