core: added a new RemovedLogEvent

When a chain reorganisation occurs we collect the logs that were deleted
during the chain reorganisation. The removed logs are posted to the
event mux indicating that those were deleted during the reorg.

core/events.go

@@ -39,6 +39,9 @@ type NewMinedBlockEvent struct{ Block *types.Block }
 // RemovedTransactionEvent is posted when a reorg happens
 type RemovedTransactionEvent struct{ Txs types.Transactions }
 
+// RemovedLogEvent is posted when a reorg happens
+type RemovedLogEvent struct{ Logs vm.Logs }
+
 // ChainSplit is posted when a new head is detected
 type ChainSplitEvent struct {
 	Block *types.Block