HDFS-2976 removed the unused imports that were missed in previous commit.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1298508 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -110,7 +110,6 @@ import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.BlockOpResponseP
 import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.OpBlockChecksumResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.DataTransferProtos.Status;
 import org.apache.hadoop.hdfs.security.token.block.BlockTokenIdentifier;
-import org.apache.hadoop.hdfs.security.token.block.InvalidBlockTokenException;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifier;
 import org.apache.hadoop.hdfs.server.common.HdfsServerConstants;
 import org.apache.hadoop.hdfs.server.common.UpgradeStatusReport;
@@ -132,7 +131,6 @@ import org.apache.hadoop.security.token.Token;
 import org.apache.hadoop.security.token.TokenRenewer;
 import org.apache.hadoop.util.DataChecksum;
 import org.apache.hadoop.util.Progressable;
-import org.apache.hadoop.hdfs.security.token.block.InvalidBlockTokenException;
 
 import com.google.common.base.Preconditions;