[PATCH 2/6] engine: pass vclock instead of lsn to collect_garbage callback

[Vladimir Davydov]

On Mon, Nov 26, 2018 at 08:41:47PM +0300, Konstantin Osipov wrote:
> * Vladimir Davydov <vdavydov.dev at gmail.com> [18/11/26 10:27]:
> > First, this is consistent with other engine callbacks, such as
> > checkpoint or backup.
> > 
> > Second, a vclock can be used as a search key in a vclock set,
> > which in turn can make code more straightforward, e.g. look how
> > this patch simplifies vy_log_prev_checkpoint().
> 
> OK to push.

Pushed to 2.1