fix get_unspent_txouts() for multisig with same addresses but different ...

...signatures required
Sorry I keep coming back to this, but I'm pretty sure that this logic shouldn't be here. For instance, we may be able to use this: https://github.com/CounterpartyXCP/counterpartyd/blob/develop/lib/blocks.py#L1057-L1075 and `util.construct_array()` for the last line.