Remove disconnect on unrequested transaction.

BitcoinJ, and possibly other wallets, don't follow the spec of sending an
inventory message and allowing the remote peer to decide whether or not
they want to request the transaction via a getdata message.  Unfortuantely
the reference implementation permits unrequested data, so it has allowed
wallets that don't follow the spec to proliferate.

While this is not ideal, this commit removes the functionality which
disconnects peers for sending unsolicited transactions to provide
interoperability.