HADOOP-17629. TestRPC#testAuthorization fails. (#8004)

Author: szetszwo

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/ipc/TestRPC.java

@@ -702,6 +702,8 @@ public void testAuthorization() throws Exception {
 
     // Expect to succeed
     myConf.set(ACL_CONFIG, "*");
+    RPC.setProtocolEngine(myConf, TestRpcService.class, ProtobufRpcEngine2.class);
+
     doRPCs(myConf, false);
 
     // Reset authorization to expect failure