Currently, if a container removal has failed for some reason,
any client waiting for removal (e.g. `docker run --rm`) is
stuck, waiting for removal to succeed while it has failed already.
For more details and the reproducer, please check
https://github.com/moby/moby/issues/34945
This commit addresses that by allowing `ContainerWait()` with
`container.WaitCondition == "removed"` argument to return an
error in case of removal failure. The `ContainerWaitOKBody`
stucture returned to a client is amended with a pointer to `struct Error`,
containing an error message string, and the `Client.ContainerWait()`
is modified to return the error, if any, to the client.
Note that this feature is only available for API version >= 1.34.
In order for the old clients to be unstuck, we just close the connection
without writing anything -- this causes client's error.
Now, docker-cli would need a separate commit to bump the API to 1.34
and to show an error returned, if any.
[v2: recreate the waitRemove channel after closing]
[v3: document; keep legacy behavior for older clients]
[v4: convert Error from string to pointer to a struct]
[v5: don't emulate old behavior, send empty response in error case]
[v6: rename legacy* vars to include version suffix]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>