SmrPort: add selectAndRemoveGood method
SmrPort: add selectAndRemoveGood method

This is used to simplify `doDowngrade`, which complements the
`selectAndAddGood` method used in `doUpgrade`.

hemberger/smr,smrealms/smr,hemberger/smr,hemberger/smr,hemberger/smr,smrealms/smr,smrealms/smr