Kylo should install successfully without requiring Spark to be present (optional)
It should be possible to remove the dependency of Spark from the install process by using a overridable default for SPARK_PROFILE variable in update-nars.sh
Also, can fix spark-shell service so it fails to start if Spark is not present.
NOTE the default will require spark to be present. will add a check in rpm install, or setup wizard, to fail fast.