fix username

doc/design/cluster_train/data_dispatch.md

@@ -127,15 +127,15 @@ paddle pfs cp random_images-*-of-* /pfs/$DATACENTER/home/$USER/folder/
 ```
 # config file
 [datacenter_1]
-username=wuyi
-usercert=wuyi.pem
-userkey=wuyi-key.pem
+username=user
+usercert=user.pem
+userkey=user-key.pem
 endpoint=datacenter1.paddlepaddle.org
 
 [datacenter_2]
-username=wuyi
-usercert=wuyi.pem
-userkey=wuyi-key.pem
+username=user
+usercert=user.pem
+userkey=user-key.pem
 endpoint=datacenter2.paddlepaddle.org
 ```
 ## TODO