At the moment codebase is relying on elasticsearch 2, which is not
maintained and EOLed a while ago.
With that there is no known obvious benefits of using elasticsearch
over sqlalchemy, while maintenance cost is way higher.
Thus, we deprecate the elasticsearch DB engine with goal to remove
it in next release.
Change-Id: I3471518af8883a44072b271b7ec6bfb073b3bb7a
Signed-off-by: Dmitriy Rabotyagov <noonedeadpunk@gmail.com>
a4a7250732