The Logentries service will be discontinued next week:

> Dear Logentries user,
>
> We have identified you as the owner of, or collaborator of, a Logentries account.
>
> The Logentries service will be discontinued on November 15th, 2022. This means that your Logentries account access will be removed and all your log data will be permanently deleted on this date.
>
> Next Steps
> If you are interested in an alternative Rapid7 log management solution, InsightOps will be available for purchase through December 16th, 2022. Please note, there is no support to migrate your existing Logentries account to InsightOps.
>
> Thank you for being a valued user of Logentries.
>
> Thank you,
> Rapid7 Customer Success

There is no reason to preserve this code in Moby as a result.

Signed-off-by: Bjorn Neergaard <bneergaard@mirantis.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

A validation step was added to prevent the daemon from considering "logentries"
as a dynamically loaded plugin, causing it to continue trying to load the plugin;

    WARN[2023-12-12T21:53:16.866857127Z] Unable to locate plugin: logentries, retrying in 1s
    WARN[2023-12-12T21:53:17.868296836Z] Unable to locate plugin: logentries, retrying in 2s
    WARN[2023-12-12T21:53:19.874259254Z] Unable to locate plugin: logentries, retrying in 4s
    WARN[2023-12-12T21:53:23.879869881Z] Unable to locate plugin: logentries, retrying in 8s

But would ultimately be returned as an error to the user:

    docker container create --name foo --log-driver=logentries nginx:alpine
    Error response from daemon: error looking up logging plugin logentries: plugin "logentries" not found

With the additional validation step, an error is returned immediately:

    docker container create --log-driver=logentries busybox
    Error response from daemon: the logentries logging driver has been deprecated and removed

A migration step was added on container restore. Containers using the
"logentries" logging driver are migrated to use the "local" logging driver:

    WARN[2023-12-12T22:38:53.108349297Z] migrated deprecated logentries logging driver  container=4c9309fedce75d807340ea1820cc78dc5c774d7bfcae09f3744a91b84ce6e4f7 error="<nil>"

As an alternative to the validation step, I also considered using a "stub"
deprecation driver, however this would not result in an error when creating
the container, and only produce an error when starting:

    docker container create --name foo --log-driver=logentries nginx:alpine
    4c9309fedce75d807340ea1820cc78dc5c774d7bfcae09f3744a91b84ce6e4f7

    docker start foo
    Error response from daemon: failed to create task for container: failed to initialize logging driver: the logentries logging driver has been deprecated and removed
    Error: failed to start containers: foo

For containers, this validation is added in the backend (daemon). For services,
this was not sufficient, as SwarmKit would try to schedule the task, which
caused a close loop;

    docker service create --log-driver=logentries --name foo nginx:alpine
    zo0lputagpzaua7cwga4lfmhp
    overall progress: 0 out of 1 tasks
    1/1: no suitable node (missing plugin on 1 node)
    Operation continuing in background.

    DEBU[2023-12-12T22:50:28.132732757Z] Calling GET /v1.43/tasks?filters=%7B%22_up-to-date%22%3A%7B%22true%22%3Atrue%7D%2C%22service%22%3A%7B%22zo0lputagpzaua7cwga4lfmhp%22%3Atrue%7D%7D
    DEBU[2023-12-12T22:50:28.137961549Z] Calling GET /v1.43/nodes
    DEBU[2023-12-12T22:50:28.340665007Z] Calling GET /v1.43/services/zo0lputagpzaua7cwga4lfmhp?insertDefaults=false
    DEBU[2023-12-12T22:50:28.343437632Z] Calling GET /v1.43/tasks?filters=%7B%22_up-to-date%22%3A%7B%22true%22%3Atrue%7D%2C%22service%22%3A%7B%22zo0lputagpzaua7cwga4lfmhp%22%3Atrue%7D%7D
    DEBU[2023-12-12T22:50:28.345201257Z] Calling GET /v1.43/nodes

So a validation was added in the service create and update endpoints;

    docker service create --log-driver=logentries --name foo nginx:alpine
    Error response from daemon: the logentries logging driver has been deprecated and removed

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>