dhcp-server: T9267: drop standalone substring "length" option

The byte length compared by a hostname/vendor-class-id "substring"
match is always derived from "value" for a meaningful equality test:
a shorter length never matches (comparing fewer option bytes against
the full value literal), and a longer one is silently clamped by Kea
to the available bytes, turning what looks like a prefix match into
an exact match of the whole remainder. There is no legitimate use for
setting it independently of "value", so drop the leaf rather than add
another verify() constraint around it.

Reported by alexk37 in review of PR #5436.

0 files changed, 0 insertions, 0 deletions