rcm: remove outdated comment

PushCompose() does not inject a local target anymore.

internal/rcm/api.go

@@ -206,7 +206,6 @@ func (api *API) submit(writer http.ResponseWriter, request *http.Request, _ http
 
 	// Push the requested compose to the store
 	composeUUID := uuid.New()
-	// nil is used as an upload target, because LocalTarget is already used in the PushCompose function
 	err = api.store.PushCompose(imageType, composeUUID, &blueprint.Blueprint{}, repoConfigs, packages, buildPackages, 0, nil)
 	if err != nil {
 		if api.logger != nil {