v1.3.2

Forbid removed node from being a `Candidate` (#476)

* modify `TestRaft_RemoveFollower` to check removed node state

* add test to verify that a removed node is not able to vote

* do not transition to `Candidate` state if not part of stable configuration

* add some comments to the tests

* do not return if not transitioning state

* add wait loop to test

* remove test related to removed node voting

* check `inConfig` instead of `hasVote`

* updating warn log message to be more accurate