VOL-2154 : Moving back db/model to voltha-go repo

- Package imports and dockerfiles updated
- Left backend.go in voltha-lib-go

Amendments:

- Adjusted proto imports in unit tests
- Adjusted references to db/model in unit tests
- Integrate voltha-lib-go updates

Change-Id: I2d168c516a238222f0371a7bcb672d2b06796838
diff --git a/rw_core/core/transaction.go b/rw_core/core/transaction.go
index 697e811..4ce00f9 100644
--- a/rw_core/core/transaction.go
+++ b/rw_core/core/transaction.go
@@ -296,14 +296,14 @@
 	// Stop monitoring the key (applies only when there has been no transaction switch over)
 	if c.monitorCh != nil {
 		close(c.monitorCh)
-		ctx.kvClient.Put(c.txnKey, TRANSACTION_COMPLETE, ctx.kvOperationTimeout, false)
+		ctx.kvClient.Put(c.txnKey, TRANSACTION_COMPLETE, ctx.kvOperationTimeout)
 	}
 	return nil
 }
 
 func (c *KVTransaction) Delete() error {
 	log.Debugw("delete", log.Fields{"txn": c.txnId})
-	return ctx.kvClient.Delete(c.txnKey, ctx.kvOperationTimeout, false)
+	return ctx.kvClient.Delete(c.txnKey, ctx.kvOperationTimeout)
 }
 
 // holdOnToTxnUntilProcessingCompleted renews the transaction lease until the transaction is complete.  durationInSecs