form: fix captcha

wouldn't compile (not sure why i didn't notice) and after fixing, the
check was being performed after deleting the invite so would always
fail.

api.go

@@ -628,6 +628,11 @@ func (app *appContext) NewUser(gc *gin.Context) {
 	var req newUserDTO
 	gc.BindJSON(&req)
 	app.debug.Printf("%s: New user attempt", req.Code)
+	if app.config.Section("captcha").Key("enabled").MustBool(false) && !app.verifyCaptcha(req.Code, req.CaptchaID, req.CaptchaText) {
+		app.info.Printf("%s: New user failed: Captcha Incorrect", req.Code)
+		respond(400, "errorCaptcha", gc)
+		return
+	}
 	if !app.checkInvite(req.Code, false, "") {
 		app.info.Printf("%s New user failed: invalid code", req.Code)
 		respond(401, "errorInvalidCode", gc)
@@ -651,11 +656,6 @@ func (app *appContext) NewUser(gc *gin.Context) {
 		respond(400, "errorNoEmail", gc)
 		return
 	}
-	if app.config.Section("captcha").Key("enabled").MustBool(false) && !verifyCaptcha(req.Captcha) {
-		app.info.Printf("%s: New user failed: Captcha Incorrect", req.Code)
-		respond(400, "errorCaptcha", gc)
-		return
-	}
 	f, success := app.newUser(req, false)
 	if !success {
 		f(gc)