Ptarmigan spoil lnd's announcement_signatures before funding_locked.
lnd: a575b5679d116fcadb0f5b8dd943953e11646de4
BOLT7:
A recipient node:
- if it has not sent funding_locked:
- MAY defer handling the announcement_signatures until after it has sent funding_locked
- otherwise:
- MUST ignore it.
Ptarmigan spoil lnd's announcement_signatures before funding_locked.