ID-FFv1.2 idp: in idff12_endpoints.sso for invalid message, return explicit message with HTTP error
ID-FFv1.2 idp: in idff12_endpoints.sso for invalid message, return explicit message with HTTP error

BryceLohr/authentic,adieu/authentic2,pu239ppy/authentic2,adieu/authentic2,BryceLohr/authentic,incuna/authentic,incuna/authentic,BryceLohr/authentic,adieu/authentic2,pu239ppy/authentic2,incuna/authentic,BryceLohr/authentic,pu239ppy/authentic2,pu239ppy/authentic2,adieu/authentic2,incuna/authentic,incuna/authentic