plugin: remove unused pluginRegistryService

It wrapped the regular registry service, but the ResolveRepository() function
was not called anywhere.

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

plugin/manager.go

@@ -14,7 +14,6 @@ import (
 
 	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/content/local"
-	"github.com/docker/distribution/reference"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/pkg/authorization"
 	"github.com/docker/docker/pkg/containerfs"
@@ -83,25 +82,8 @@ type controller struct {
 	timeoutInSecs int
 }
 
-// pluginRegistryService ensures that all resolved repositories
-// are of the plugin class.
-type pluginRegistryService struct {
-	registry.Service
-}
-
-func (s pluginRegistryService) ResolveRepository(name reference.Named) (repoInfo *registry.RepositoryInfo, err error) {
-	repoInfo, err = s.Service.ResolveRepository(name)
-	if repoInfo != nil {
-		repoInfo.Class = "plugin"
-	}
-	return
-}
-
 // NewManager returns a new plugin manager.
 func NewManager(config ManagerConfig) (*Manager, error) {
-	if config.RegistryService != nil {
-		config.RegistryService = pluginRegistryService{config.RegistryService}
-	}
 	manager := &Manager{
 		config: config,
 	}