This reverts commit a9c0b8f264.
From Joseph Sutton:
> I found that this commit would result in `KRB5KRB_AP_ERR_BAD_INTEGRITY`
> errors in Samba whenever explicit FAST armor was present. Reverting the
> commit made FAST work again.
> It should be safe to use `tgs_ac` here, since it will always be non-NULL if
> `r->explicit_armor_present` is true. Maybe a local variable
> `explicit_armor_present` (which would be assigned to
> `r->explicit_armor_present` before the function returns successfully) would
> help a static analyser to deduce that its value doesn't change within the
> function, and that `tgs_ac != NULL` still holds.
a9c0b8f264 (commitcomment-95581208)
cb5262014a