Andrew Chow 43811e6338 Fix PSBT deserialization of 0-input transactions
0-input transactions can be ambiguously deserialized as being witness
transactions. Since the unsigned transaction is never serialized as
a witness transaction as it has no witnesses, we should always
deserialize it as a non-witness transaction and set the serialization
flags as such.

Also always serialize the unsigned transaction as a non-witness transaction.
2018-08-13 14:59:31 -07:00
..