enable_elasticsearch option is already added,in https://github.com/openstack/kolla/blob/master/ansible/group_vars/all.yml#L303
elastic search enable or disable depends on "enable_central_logging" not on "enable_elasticsearch" in globals.yml file.
So remove enable_elasticsearch option from global.yml

This reverts commit f581c81e.
Change-Id: I1ceff747d7b978dc82efc55fda72b9b98c272f0d