Fix panic by skipping any candidates that returned ErrNotReplica during StopReplication phase
Fix panic by skipping any candidates that returned ErrNotReplica during StopReplication phase

Signed-off-by: Andrew Mason <8a240ff75aa1467ba5eba4db0c8200b61262547e@slack-corp.com>

mahak/vitess,tinyspeck/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,mahak/vitess,tinyspeck/vitess,tinyspeck/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,tinyspeck/vitess,tinyspeck/vitess,vitessio/vitess,tinyspeck/vitess,tinyspeck/vitess,vitessio/vitess