`--single-transaction` and `--clean` are incompatible

[jonathan-s]

I'm having issues with single-transaction and clean. As mentioned here they seem to be incompatible. So a sane default should be to not be using a single transaction. Ideally, if you try setting both it should throw a helpful error.

[jonathan-s]

Seems to be working fine either way when I was using the PostgresBinaryDumpConnector.