directory structure change to work with glide

glide has its own requirements. My previous workaround caused me some
code checkin errors. Need to fix this.

weed/topology/cluster_commands.go

@@ -0,0 +1,31 @@
+package topology
+
+import (
+	"github.com/chrislusf/raft"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage"
+)
+
+type MaxVolumeIdCommand struct {
+	MaxVolumeId storage.VolumeId `json:"maxVolumeId"`
+}
+
+func NewMaxVolumeIdCommand(value storage.VolumeId) *MaxVolumeIdCommand {
+	return &MaxVolumeIdCommand{
+		MaxVolumeId: value,
+	}
+}
+
+func (c *MaxVolumeIdCommand) CommandName() string {
+	return "MaxVolumeId"
+}
+
+func (c *MaxVolumeIdCommand) Apply(server raft.Server) (interface{}, error) {
+	topo := server.Context().(*Topology)
+	before := topo.GetMaxVolumeId()
+	topo.UpAdjustMaxVolumeId(c.MaxVolumeId)
+
+	glog.V(4).Infoln("max volume id", before, "==>", topo.GetMaxVolumeId())
+
+	return nil, nil
+}