[Tarantool-patches] [PATCH 1/2] replication: introduce ballot.can_be_leader

[Vladislav Shpilevoy]

Hi! Thanks for the review!

> Hi and thanks for the patch!
> 
> It's all good except the field name. It's rather long IMO, and may be
> confused with bootsrap leader, which we try to find using ballots.
> 
> Wouldn't "can be candidate", or "is_election_candidate" be better?

`is_election_candidate` is even longer. I thought about `can_be_candidate`
firstly, but then I realized that it is the same as `can_be_leader`, because
the purpose of a candidate is to become a leader anyway. And we are looking
for a leader, not a candidate. The latter is just an intermediate state.

I shortened the name to `can_lead`. Ok?

As for inability to boot a cluster we might in the future add a flag `can_boot`
if necessary. See new patch in v2.