Fixed change when avatar mode is enabled

If avatar mode is enabled, the change is lost (it's not sent at all, so it's lost as excess fees). This pull request fixes that.

I haven't taken time to test that. It'd be nice if some people could confirm on testnet that the change is correctly sent in these situations combined in all possible ways:
* coin control activated or not
* coins sent with an explicit change address defined in coin control or not
* avatar mode enabled or not

**In the meantime avatar mode must absolutely be disabled when using Peerunity** (it's disabled by default).