[VOL-1550] Support for OLT hard reboot with ONU connected

Change-Id: I67642d847d2308f8abf8e9b90986eeecf65b2a41
diff --git a/vendor/github.com/opencord/voltha-go/db/model/revision.go b/vendor/github.com/opencord/voltha-go/db/model/revision.go
index 74ae3f7..4e606f1 100644
--- a/vendor/github.com/opencord/voltha-go/db/model/revision.go
+++ b/vendor/github.com/opencord/voltha-go/db/model/revision.go
@@ -17,6 +17,7 @@
 
 import (
 	"github.com/opencord/voltha-go/db/kvstore"
+	"time"
 )
 
 type Revision interface {
@@ -43,6 +44,8 @@
 	GetData() interface{}
 	GetNode() *node
 	LoadFromPersistence(path string, txid string, blobs map[string]*kvstore.KVPair) []Revision
+	SetLastUpdate(ts ...time.Time)
+	GetLastUpdate() time.Time
 	UpdateData(data interface{}, branch *Branch) Revision
 	UpdateChildren(name string, children []Revision, branch *Branch) Revision
 	UpdateAllChildren(children map[string][]Revision, branch *Branch) Revision