remove the redundant type conversion

weed/storage/volume.go

@@ -208,8 +208,8 @@ func (v *Volume) ToVolumeInformationMessage() *master_pb.VolumeInformationMessag
 		Id:               uint32(v.Id),
 		Size:             size,
 		Collection:       v.Collection,
-		FileCount:        uint64(v.FileCount()),
-		DeleteCount:      uint64(v.DeletedCount()),
+		FileCount:        v.FileCount(),
+		DeleteCount:      v.DeletedCount(),
 		DeletedByteCount: v.DeletedSize(),
 		ReadOnly:         v.noWriteOrDelete,
 		ReplicaPlacement: uint32(v.ReplicaPlacement.Byte()),