Enabling ANSIBLE_INJECT_FACT_VARS does result in a performance
regression as each variable loaded to runtime slows down task
execution.
We disable ANSIBLE_INJECT_FACT_VARS in OSA by default for a while,
so ELK role should also be able to run with this setting disabled.
Change-Id: Ibffc09cdb4f9289ddad38211ccb0265642b4321f
1d52793ec6