* Vladimir Davydov <vdavydov.dev@xxxxxxxxx> [18/10/05 00:11]:
Do some refactoring intended to make the code of gc_run() easier for
understanding:
- Remove gc_state::checkpoint_vclock. It was used to avoid rerunning
engine gc callback in case no checkpoint was deleted. Since we
maintain a list of all available checkpoints, we don't need it for
this anymore - we can run gc only if a checkpoint was actually
removed from the list.
- Rename gc_state::wal_vclock back to gc_state::vclock.
- Use bool variables with descriptive names instead of comparing
vclock signatures.
- Add some comments.
