Remove prepending of v1RegistryURL to the repo (#47)

* Default registry value is not  but v1RegistryURL

* Handle test (not sure about its relevancy

Co-authored-by: Ymage <heltem+git@o2php.com>

cmd/kaniko-docker/main.go

@@ -264,7 +264,7 @@ func createDockerCfgFile(username, password, registry string) error {
 }
 
 func buildRepo(registry, repo string) string {
-	if registry == "" {
+	if registry == "" || registry == v1RegistryURL {
 		// No custom registry, just return the repo name
 		return repo
 	}