We should display a nicer error here

[jacobstanley]

$ hh rm -r foo/
java.io.IOException
rename destination directory is not empty: /user/hadoop/.Trash/Current/user/hadoop/foo/
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.validateRenameOverwrite(FSDirectory.java:780)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.unprotectedRenameTo(FSDirectory.java:645)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.renameTo(FSDirectory.java:472)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.renameToInternal(FSNamesystem.java:3694)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.renameTo(FSNamesystem.java:3655)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.rename2(NameNodeRpcServer.java:749)
at org.apache.hadoop.hdfs.server.namenode.AuthorizationProviderProxyClientProtocol.rename2(AuthorizationProviderProxyClientProtocol.java:269)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.rename2(ClientNamenodeProtocolServerSideTranslatorPB.java:571)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:587)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1026)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2013)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2009)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1614)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2007)