VOL-1247 : Modified change tuple to include previous and latest data

VOL-1214 : Fixed logs to use the proper mechanism

- Added missing license
- Moved one change tuple statement which would not include proper info

Change-Id: I5a02f6fe92c8b193642294d62f4413ac6edc0c62
diff --git a/db/model/persisted_revision.go b/db/model/persisted_revision.go
index 05c4090..774b77e 100644
--- a/db/model/persisted_revision.go
+++ b/db/model/persisted_revision.go
@@ -19,7 +19,6 @@
 	"bytes"
 	"compress/gzip"
 	"encoding/json"
-	"fmt"
 	"github.com/golang/protobuf/proto"
 	"github.com/opencord/voltha-go/common/log"
 	"io/ioutil"
@@ -104,7 +103,7 @@
 		}
 	}
 	if err := json.Unmarshal(output, &data); err != nil {
-		fmt.Errorf("problem to unmarshal data - %s", err.Error())
+		log.Errorf("problem to unmarshal data - %s", err.Error())
 	}
 
 	stop := time.Now()