* Sense HA HDFS settings and remove permission restrictions during regular execution.
This PR adds integration tests for HA-Enabled HDFS deployments, both regular and secured.
The Mini HDFS fixture has been updated to optionally run in HA-Mode. A new test suite has
been added for reproducing the effects of a Namenode failing over during regular repository
usage. Going forward, the HDFS Repository will still be subject to its self imposed permission
restrictions during normal use, but will no longer restrict them when running against an HA
enabled HDFS cluster. Instead, the plugin will rely on the provided security policy and not
further restrict the permissions so that the transparent operation to failover to a different
Namenode in the client does not raise security exceptions. Additionally, we are now testing the
secure mode with SASL based wire encryption of data between Elasticsearch and HDFS. This
includes a missing library (commons codec) in order to support this change.
