remove unused code

weed/topology/topology.go

@@ -201,13 +201,6 @@ func (t *Topology) NextVolumeId() (needle.VolumeId, error) {
 	return next, nil
 }
 
-// deprecated
-func (t *Topology) HasWritableVolume(option *VolumeGrowOption) bool {
-	vl := t.GetVolumeLayout(option.Collection, option.ReplicaPlacement, option.Ttl, option.DiskType)
-	active, _ := vl.GetActiveVolumeCount(option)
-	return active > 0
-}
-
 func (t *Topology) PickForWrite(count uint64, option *VolumeGrowOption) (string, uint64, *VolumeLocationList, error) {
 	vid, count, datanodes, err := t.GetVolumeLayout(option.Collection, option.ReplicaPlacement, option.Ttl, option.DiskType).PickForWrite(count, option)
 	if err != nil {