Trim spaces on submitted usernames

server/login/login.go

@@ -252,7 +252,7 @@ func (l *Login) handleLogin(w http.ResponseWriter, req *http.Request, sess *logi
 	sess.Reset()
 
 	// Case-fold usernames to lowercase.
-	username := strings.ToLower(req.FormValue("username"))
+	username := strings.ToLower(strings.TrimSpace(req.FormValue("username")))
 	password := req.FormValue("password")
 
 	// If the request is a POST, attempt login with username/password.