Cannot add secret to service using secret id

Description

Using docker service update --add-secret I can only use secret name to reference a secret to add, not its id.

Steps to reproduce the issue:

> "secret" | docker secret create my-secret -
p6xb5qclxhrasp698a97e5fx0

> docker service ls
ID                  NAME                          MODE                REPLICAS            IMAGE                                     PORTS
411ougndilsw        friism-stack_friism-service   replicated          1/1                 nginx:latest

> docker service update --secret-add p6x friism-stack_friism-service
secret not found: p6x
> docker service update --secret-add p6xb5qclxhrasp698a97e5fx0 friism-stack_friism-service
secret not found: p6xb5qclxhrasp698a97e5fx0

> docker service update --secret-add my-secret friism-stack_friism-service
friism-stack_friism-service
overall progress: 1 out of 1 tasks
1/1: running   [==================================================>]
verify: Service converged

Describe the results you received:

secret not found: p6xb5qclxhrasp698a97e5fx0

Describe the results you expected:

Secret added to service.

Output of docker version:

Client:
 Version:       17.12.0-ce-rc4
 API version:   1.30 (downgraded from 1.35)
 Go version:    go1.9.2
 Git commit:    6a2c058
 Built: Wed Dec 20 15:53:56 2017
 OS/Arch:       windows/amd64

Server:
 Engine:
  Version:      ucp/3.0.0-0135340
  API version:  1.30 (minimum version 1.20)
  Go version:   go1.9.2
  Git commit:   0135340
  Built:        Wed Jan  3 10:06:20 UTC 2018
  OS/Arch:      linux/amd64
  Experimental: false

Start at the docker service update --secret-add CLI entry point and trace how the supplied secret reference is looked up. Verify the behavior with the reproduction commands, then ensure both a secret name and the reported secret ID can add the secret to the service.