Resolve: Add option to disable healthcheck for storagedriver in registry

It was originally reported at https://forum.gitlab.com/t/docker-registry-not-available/8049

The error:

{
  "code":"UNAVAILABLE",
  "message":"service unavailable",
  "detail":"health check failed: please see /debug/health"
}

Resolution

In gitlab.rb, add the following line to disable registry storagedriver health checks:

registry['storagedriver_health_enabled'] = false

The default is true.

Related issues

Closes #3382 (closed).