fix: exit block comparison (#70)

* first commit

* first commit

* first commit

* first commit

Author: freemanzMrojo

stats/pos/writer.go

@@ -408,8 +408,10 @@ func (s *Staker) createSingleValidatorStats(ev *types.Event, info *StakerInforma
 			if prevEntry.LockedVET != validator.LockedVET {
 				flags["stake_changed"] = validator.LockedVET - prevEntry.LockedVET
 			}
-			if prevEntry.ExitBlock != prevEntry.ExitBlock {
-				flags["exit_block_changed"] = prevEntry.ExitBlock
+			if prevEntry.ExitBlock != nil && validator.ExitBlock != nil {
+				if *prevEntry.ExitBlock != *validator.ExitBlock {
+					flags["exit_block_changed"] = *validator.ExitBlock
+				}
 			}
 		}
 		if prevEntry == nil || prevEntry.Online != validator.Online {