When a user or client intend to delete a datafeed
and its job, there is benefit into ensuring the
datafeed has gracefully stopped (ie no data loss).
In constrast, the desired behaviour is to stop and
delete the datafeed as quickly as possible.
This change adds a force option to the delete
datafeed action. When the delete is forced,
the datafeed is isolated, its task removed and,
finally, the datafeed itself is removed from the
metadata.
relates elastic/x-pack-elasticsearch#1533
Original commit: elastic/x-pack-elasticsearch@5ae0168bf2
3f6e640f90