need mechanism for updating HDFS delegation tokens associated with container launch contexts

During the launch of a container, the required delegation tokens (e.g. HDFS) are passed to the launch context. If those tokens expire and the container requires a restart the restart attempt will fail. Sample log output:

2014-10-06 18:37:28,609 WARN ipc.Client (Client.java:run(675)) - Exception encountered while connecting to the server : org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.token.SecretManager$InvalidToken): token (HDFS_DELEGATION_TOKEN token 124 for hbase) can't be found in cache