Fix full config update (#240)

Why I did it
GNMI full config end to end test is broken.

How I did it
Fix yang validation part to send file name to python code.

How to verify it
Run gnmi unit test and end to end test.

sonic_data_client/mixed_db_client.go

@@ -1353,7 +1353,7 @@ func (c *MixedDbClient) SetFullConfig(delete []*gnmipb.Path, replace []*gnmipb.U
 		return err
 	}
 
-	PyCodeInGo := fmt.Sprintf(PyCodeForYang, ietf_json_val)
+	PyCodeInGo := fmt.Sprintf(PyCodeForYang, fileName)
 	err = RunPyCode(PyCodeInGo)
 	if err != nil {
 		return fmt.Errorf("Yang validation failed!")