Yes we can.  I've replaced "mapreduce.job.credentials.binary" with SecurityUtils.MAPREDUCE_JOB_CREDENTIALS_BINARY and "HADOOP_TOKEN_FILE_LOCATION" with UserGroupInformation.HADOOP_TOKEN_FILE_LOCATION in my subsequent commit.

Note that a constant for "mapreduce.job.credentials.binary" is defined in org.apache.hadoop.mapreduce.security.TokenCache, but it is package private, so I can't access it.  A public constant for "mapreduce.job.credentials.binary" is also defined in HCatConstants, but it seems strange (and unreliable) to add a dependency on hcatalog to azkaban-plugins.