Revert "lib/model: Emit LocalDiskUpdated events on detecting local changes"

This reverts commit 5a7fad0bcd.

lib/events/events.go

@@ -27,7 +27,6 @@ const (
 	DeviceRejected
 	DevicePaused
 	DeviceResumed
-	LocalDiskUpdated
 	LocalIndexUpdated
 	RemoteIndexUpdated
 	ItemStarted
@@ -62,8 +61,6 @@ func (t EventType) String() string {
 		return "DeviceDisconnected"
 	case DeviceRejected:
 		return "DeviceRejected"
-	case LocalDiskUpdated:
-		return "LocalDiskUpdated"
 	case LocalIndexUpdated:
 		return "LocalIndexUpdated"
 	case RemoteIndexUpdated: