Changing name of "Jar" jobs to "MapReduce"

Per savanna-api change https://review.openstack.org/#/c/62058, the name
of Jar jobs has been changed to MapReduce.  Previously created jobs
will still work.

Implements:  blueprint edp-oozie-java-action

Change-Id: If8e4b2c2f40cf8520c204127b40724c0b12b4e3b
Merge "Changing name of "Jar" jobs to "MapReduce""