Remove force selection of payment method.
a demandé de fusionner 202-formulaires-partiellement-remis-a-zero-en-cas-d-erreur-de-validation vers develop
On creation it is set, and in case of error we want to keep the one that was set. Fix a bug on no payment method defined, the mailers were going havoc. Note that we can create a service without payment bug/feature ?
Closes #202 (closed)