Startup falsely claims image missing for custom Redis images.

[MitchellRomney]

Description of problem

When using a custom Redis image (in my case, redis-stack-server:7.2.0), startup throws an error saying that the image is missing, when it isn't.

It looks like the startup script was first checking for the base redis image instead of the custom set image, causing it to actually detect that redis:7.2.0 was missing, before then applying the custom image and then falsely reporting redis-stack-server:7.2.0 was missing.

The temporary solution was as simple as just pulling redis:7.2.0, even though this image is not actually being used it allows the image validation to pass.

How reproducible

Easily, just start a new Redis server with a custom image, then restart the service.

Steps to Reproduce

1. dokku redis:create [name] -i redis/redis-stack-server -I 7.2.0-v10
2. dokku redis:restart [name]

Actual Results

Error thrown claiming that Missing image redis/redis-stack-server:7.2.0-v10 for [name].

Expected Results

Startup should continue smoothly assuming the custom image is present in docker.

Environment Information

root@[server]:~# dokku redis:info [name]
=====> [name] redis service information
       Config dir:          /var/lib/dokku/services/redis/[name]/config
       Config options:
       Data dir:            /var/lib/dokku/services/redis/[name]/data
       Dsn:                 --
       Exposed ports:       6379->XXXX
       Id:                  --
       Internal ip:         --
       Initial network:
       Links:               [app]
       Post create network:
       Post start network:
       Service root:        /var/lib/dokku/services/redis/[name]
       Status:              running
       Version:             redis/redis-stack-server:7.2.0-v10

Note: This info was printed after having manually fixed the bug, before the status would not have been running.