Add CDH_MAJOR_VERSION environment variable
Add CDH_MAJOR_VERSION environment variable

CDH_MAJOR_VERSION controls where HDFS data is written. In the future, we
can use its value to parameterise Jenkins jobs so that the right code is
run / data is generated.

Change-Id: Id2957df6d708bc6c50faf7a8a609aff5f9571662
Reviewed-on: http://gerrit.ent.cloudera.com:8080/1293
Reviewed-by: Nong Li <99a5e5f8f5911755b88e0b536d46aafa102bed41@cloudera.com>
Reviewed-by: Lenni Kuff <724b7df200764f5dc1b723c05ee6c6adabd11bb1@cloudera.com>
Tested-by: jenkins

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