[spesmilo/electrum] how electrum use UTXO from different address? (#4640)

@SomberNight it`s not a error, there are 2 utxo from 2 different address in the [transaction in testnet i created](https://www.blocktrail.com/tBTC/tx/1d3e75d5198c0b9b54a2f23ffccd0a3dc42dfced6d43b4460f16b55226cd0d65),electrum work well .

But if I do the samething in my wallet(writed by php) it goes `script failed an OP_EQUALVERIFY`, (my code in php can deal many inputs to many outputs successfully if the UTXO of inputs are in a same address).

I just **don`t understand why electrum can do it (UTXO from many different addresses) successfully?**(I am a begginer of bitcoin/blockchain)