Added cluster state version to the debug logging of shards instances used in search.

src/main/java/org/elasticsearch/action/search/type/TransportSearchTypeAction.java

@@ -404,7 +404,7 @@ public abstract class TransportSearchTypeAction extends TransportAction<SearchRe
                     sb.append(result.shardTarget());
                 }
 
-                logger.debug("Moving to second phase, based on results from: {}", sb);
+                logger.debug("Moving to second phase, based on results from: {} (cluster state version: {})", sb, clusterState.version());
             }
             moveToSecondPhase();
         }