Update healthcheck and ports

[fierlion]

Summary

This contains various release related fixes:

• add healthcheck and expose required ports.
• Update short hash to consistent length
• add init release version (-1 hard coded for now with TODO)

Implementation details

The changes are made in the codebuild steps as well as in the agent-container config file which we use to build our agent container.

Testing

$ sudo systemctl stop ecs
$ make dockerfree-agent-image # creates ecs-agent-v1.62.1.tar
$ docker load < ecs-agent-v1.62.1.tar # retags as latest automatically
$ sudo systemctl start ecs
$ docker ps # to see the healthcheck in action

CONTAINER ID   IMAGE                            COMMAND    CREATED          STATUS                    PORTS     NAMES
0c052108c229   amazon/amazon-ecs-agent:latest   "/agent"   39 seconds ago   Up 37 seconds (healthy)             ecs-agent

$ docker images # to find the latest image id
$ docker inspect

...
        "Config": {
            "Hostname": "",
            "Domainname": "",
            "User": "",
            "AttachStdin": false,
            "AttachStdout": false,
            "AttachStderr": false,
            "ExposedPorts": {
                "51678/tcp": {},
                "51679/tcp": {}
            },
...

New tests cover the changes: no

Description for the changelog

Update healthcheck and ports in dockerfree build.

Licensing

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.