updated example marathon json file with env overrides
updated example marathon json file with env overrides

andrewrothstein/hdfs,mesosphere/hdfs,edgefox/hdfs,dmitrypekar/hdfs,edgefox/hdfs,mesosphere/hdfs,dmitrypekar/hdfs,smorin/hdfs,smorin/hdfs,LLParse/hdfs,jan-zajic/mesos-hbase,jan-zajic/mesos-hbase,jmlvanre/hdfs,kensipe/hdfs,LLParse/hdfs,jan-zajic/mesos-hdfs,ryane/hdfs,kensipe/hdfs,nalingarg2/hdfs,ryane/hdfs,nalingarg2/hdfs,jmlvanre/hdfs,andrewrothstein/hdfs,jan-zajic/mesos-hdfs