EC2 has been dropped in Mitaka [1].
This patch:
* deprecates all ec2 related parameters and have no effect.
* all configuration related to ec2 is dropped.
* all keystone resources related to ec2 are not managed anymore.
* drops acceptance test for ec2 service binding.
This is a backwards-incompatible change for people who were still
deploying ec2 with Nova, but EC2 API has been deprecated for a while
(Juno).
[1] eec7a55319
Closes-Bug: #1528948
Change-Id: Ie144202648f1aae36cdca9bab5d986ae6c4d3069
d7389d44be