gofmt is different between go versions and makes everything break

.travis.yml

@@ -1,7 +1,6 @@
 language: go
 go:
  - 1.10.x
- - 1.11.x
 install:
  - go get github.com/golang/lint/golint
  - go get github.com/fzipp/gocyclo

userids.go

@@ -125,6 +125,6 @@ func ExtractUserLocalpart(userID string) (string, error) {
 	}
 	return strings.TrimPrefix(
 		strings.SplitN(userID, ":", 2)[0], // @foo:bar:8448 => [ "@foo", "bar:8448" ]
-		"@",                               // remove "@" prefix
+		"@", // remove "@" prefix
 	), nil
 }