chancloser: initiator always sends the first CloseSigned msg
chancloser: initiator always sends the first CloseSigned msg

In this commit, we update the chan closer state machine to be fully
spec compliant. A recent change was made to the spec to enforce a
strict ordering such that, the negotiation is well formed. To enact
this change, we’ll ensure that before the closeFeeNegotiation phase,
the *initiator* is always the one that sends the CloseSigned message
first.

LightningNetwork/lnd,LightningNetwork/lnd,aakselrod/lnd,aakselrod/lnd