We missed it in some corner cases where we crashed/were killed between
being told of the lockin and sending the channel_normal_operation message.
When we were restarted, we were told both sides were locked in already,
so we never updated the state.
Pull the entire "tell channeld" logic into channel_control.c, and make
it clear that we need to keep waching if we cant't tell channeld. I think
we did get this correct in practice, since funding_announce_cb has the
same test, but it's better to be clear.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>