correct bugs on web interface

otp.go

@@ -41,7 +41,7 @@ func (s *OpenVpnMgt) GenerateOTPGeneric(user string, period int, algo string, se
 	// the first code is the generic one
 	codes = append(codes, code)
 
-	for i := 1; i < 3; i++ {
+	for i := 1; i < 4; i++ {
 		code, _ = GenericTotpCode(secret, now.Add(-1*time.Second*time.Duration(period*i)), algo, digits, period)
 		codes = append(codes, code)
 	}