Fixed Issues in Apache Hadoop

Review the list of Hadoop issues that are resolved in Cloudera Runtime 7.2.11.

CDPD-26975: HADOOP-17631. Configuration ${env.VAR:-FALLBACK} should eval FALLBACK when restrictSystemProps=true.

This issue is resolved.

CDPD-5222: HADOOP-16660. ABFS: Make RetryCount in ExponentialRetryPolicy Configurable.

This issue is resolved.

HADOOP-17424: Replace HTrace with No-Op tracer. HTrace is not an active project and we no longer support it. Along with this change, the old, vulnerable jackson-databind dependency is dropped.

This issue is resolved.

HADOOP-11245: Update NFS gateway to use Netty4. The NFS gateway is rewritten using netty4.

This issue is resolved.