[Improvement] Always remove when requested

[rdehouss]

Expected Behavior

When jaas terminates, for any reason (timeouts or the user cancels the task with CTRL-C for example), the service created should be removed so that, no "garbage" is left behing
If the flag --remove asks otherwise, don't remove the service

Current Behavior

When running a task, if the task timeouts or the user cancels the task with CTRL-C for example, the service will remaining and won't be removed

Possible Solution

From what I could understand in the code, the ServiceRemove function is only called when everything went "fine" (or at least, the service "finished" somehow):

	stopStates := []swarm.TaskState{
		swarm.TaskStateComplete,
		swarm.TaskStateFailed,
		swarm.TaskStateRejected,
	}

The solution could be that the ServiceRemove function is called when the jaas process "stops" (CTRL-C must be captured) or the task timeouts.

Steps to Reproduce (for bugs)

1. docker -H "ssh://<manager>" run --rm -it -v /var/run/docker.sock:/var/run/docker.sock alexellis2/jaas run -r --image alexellis2/cows --timeout 1s
2. docker service ls will give sth like:

ID                  NAME                                    MODE                REPLICAS            IMAGE                                                                      PORTS
z9y5v33nohdo        dreamy_sammet                           replicated          0/1                 alexellis2/cows:latest

3. And docker service ps dreamy_sammet

ID                  NAME                IMAGE                    NODE                DESIRED STATE       CURRENT STATE             ERROR               PORTS
prcz9a29sd9z        dreamy_sammet.1     alexellis2/cows:latest   db-001              Shutdown            Complete 14 seconds ago

4. You see the desired state so the service is still there :)

Context

Either a task can timeout for several reason or the user might cancel the request because of a mistake or even, there is a problem with the docker daemon that cause the service/task to be stuck in "Preparing" state.

All these reasons leaves "service zoombie" behinds

Your Environment

• Version used: (latest from hub.docker.com)
• Environment name and version (e.g. Docker 1.13): Docker version 19.03.12, build 48a66213fe
• Server type and version: VM Linux 4.19.0-10-cloud-amd64 Implement service removal flag #1 SMP Debian 4.19.132-1 (2020-07-24) x86_64 GNU/Linux
• Operating System and version: Linux 4.19.0-10-cloud-amd64 Implement service removal flag #1 SMP Debian 4.19.132-1 (2020-07-24) x86_64 GNU/Linux
• Link to your project: N/A

[rdehouss]

Another case where the service aren't eventually removed is when the container image does not exist or cannot be downloaded from the registry