VOL-2154: Removed db/model from vendor folder

- Only kept reference to backend structure

Amendments:

- Adjusted imports to voltha-lib-go
- Adjusted vendor version for voltha-lib-go

Change-Id: I7e5ca9f2df7642d18e5a1835e20aa9062a8a3bd1
diff --git a/vendor/github.com/opencord/voltha-lib-go/v2/pkg/db/kvstore/client.go b/vendor/github.com/opencord/voltha-lib-go/v2/pkg/db/kvstore/client.go
index c0ebe5f..97fbec9 100644
--- a/vendor/github.com/opencord/voltha-lib-go/v2/pkg/db/kvstore/client.go
+++ b/vendor/github.com/opencord/voltha-lib-go/v2/pkg/db/kvstore/client.go
@@ -79,10 +79,10 @@
 
 // Client represents the set of APIs a KV Client must implement
 type Client interface {
-	List(key string, timeout int, lock ...bool) (map[string]*KVPair, error)
-	Get(key string, timeout int, lock ...bool) (*KVPair, error)
-	Put(key string, value interface{}, timeout int, lock ...bool) error
-	Delete(key string, timeout int, lock ...bool) error
+	List(key string, timeout int) (map[string]*KVPair, error)
+	Get(key string, timeout int) (*KVPair, error)
+	Put(key string, value interface{}, timeout int) error
+	Delete(key string, timeout int) error
 	Reserve(key string, value interface{}, ttl int64) (interface{}, error)
 	ReleaseReservation(key string) error
 	ReleaseAllReservations() error