[master] function fr_dhcpv4_encode is badly broken

[Alan DeKok]

> On Nov 6, 2020, at 10:23 AM, Chaigneau, Nicolas via Freeradius-Devel <freeradius-devel at lists.freeradius.org> wrote:
> 
> Likely since this commit:
> https://github.com/FreeRADIUS/freeradius-server/commit/3f3afcee211407fb293186416241a149136a7464

  Whoops.  We'll take a look.

  The unit tests should really catch things like this.

  Alan DeKok.