500 on /api/v1/debitscredits if id is not int

[sebastienbarbier]

Current backend crash on POST request using /api/v1/debitscredits as id is expected to be an integer but might be received as string by a wrong request.

It is expected to return 401 bad request instead of 500.

Related to a front end bug : sebastienbarbier/seven23#71