funding: unconditionally forward all received errors to client
funding: unconditionally forward all received errors to client

Previously, our old lnwire.Error message used a special code to
indicate different types of errors. With the recent push for spec
compatibility, we removed this field and instead stuffed the error into
the first byte of the error data. This works between lnd nodes, but
with other implementations they may send different errors which use a
different error scheme.

To fix this, we’ll now unconditionally return the error to the end
caller (if one exists).

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