YARN-4653 has shown me that slider isn't getting things right regarding Oozie support, as well as some other minor aspects of security
In particular, HADOOP_TOKEN_FILE_LOCATION must be read in and used for the credentials. What is in AbstractLauncher today works, but was was cut and paste from mapreduce without understanding what as going on.
- also: is AbstractLauncher setting up its environment properly, and passing down HADOOP_USER_NAME (test: make sure it is logged, verify in the AM logs on an insecure launch. Or serve it up somehow and check in a minicluster)
+ test all of this in a secure-cluster-only funtest