Update checkstyle and checkstyle plugin version to handle indentation of JDK8 Lambdas

<dependency>
  <groupId>com.puppycrawl.tools</groupId>
  <artifactId>checkstyle</artifactId>
  <version>7.3</version>
</dependency>

./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2049:          if (failedVolumes.size() > 0) {: 'if' have incorrect indentation level 10, expected level should be 8.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2050:            LOG.warn("checkDiskErrorAsync callback got {} failed volumes: {}",: 'if' child have incorrect indentation level 12, expected level should be 10.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2052:          } else {: 'if rcurly' have incorrect indentation level 10, expected level should be 8.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2053:            LOG.debug("checkDiskErrorAsync: no volume failures detected");: 'else' child have incorrect indentation level 12, expected level should be 10.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2054:          }: 'else rcurly' have incorrect indentation level 10, expected level should be 8.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2055:          lastDiskErrorCheck = Time.monotonicNow();: 'block' child have incorrect indentation level 10, expected level should be 8.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2056:          handleVolumeFailures(failedVolumes);: 'block' child have incorrect indentation level 10, expected level should be 8.
./hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java:2057:        });: 'block rcurly' have incorrect indentation level 8, expected level should be 6.