update andrewor's comments

Author: lianhuiwang

network/shuffle/src/main/java/org/apache/spark/network/shuffle/ExternalShuffleBlockResolver.java

@@ -108,11 +108,9 @@ public ManagedBuffer getBlockData(String appId, String execId, String blockId) {
 
     if ("org.apache.spark.shuffle.hash.HashShuffleManager".equals(executor.shuffleManager)) {
       return getHashBasedShuffleBlockData(executor, blockId);
-    } else if ("org.apache.spark.shuffle.sort.SortShuffleManager".equals(executor.shuffleManager)) {
+    } else if ("org.apache.spark.shuffle.sort.SortShuffleManager".equals(executor.shuffleManager)
+      || "org.apache.spark.shuffle.unsafe.UnsafeShuffleManager".equals(executor.shuffleManager)) {
       return getSortBasedShuffleBlockData(executor, shuffleId, mapId, reduceId);
-    } else if ("org.apache.spark.shuffle.unsafe.UnsafeShuffleManager".equals(
-            executor.shuffleManager)) {
-        return getSortBasedShuffleBlockData(executor, shuffleId, mapId, reduceId);
     } else {
       throw new UnsupportedOperationException(
         "Unsupported shuffle manager: " + executor.shuffleManager);