See testcase:
- imported wallet with addr1 and addr2
- three txs: tx1 funds addr1, tx2 funds addr2, tx3 spends all
- if we rm addr1 from the wallet,
- previously both tx1 and tx3 was removed (as tx3 is a child of tx1)
- now only tx1 is removed (tx3 still relates to the wallet via addr2)
fixes https://github.com/spesmilo/electrum/issues/7587