fix wrong untag when using rmi via id

server.go

@@ -995,6 +995,9 @@ func (srv *Server) deleteImage(img *Image, repoName, tag string) ([]APIRmi, erro
 			parsedRepo := strings.Split(repoAndTag, ":")[0]
 			if strings.Contains(img.ID, repoName) {
 				repoName = parsedRepo
+				if len(strings.Split(repoAndTag, ":")) > 1 {
+					tag = strings.Split(repoAndTag, ":")[1]
+				}
 			} else if repoName != parsedRepo {
 				// the id belongs to multiple repos, like base:latest and user:test,
 				// in that case return conflict