Fixing device identifier is null issue

components/device-mgt-extensions/org.wso2.carbon.device.mgt.extensions.device.type.deployer/src/main/java/org/wso2/carbon/device/mgt/extensions/device/type/deployer/template/dao/DeviceTypePluginDAO.java

@@ -67,6 +67,7 @@ public class DeviceTypePluginDAO {
 
             if (resultSet.next()) {
                 device = new Device();
+                device.setDeviceIdentifier(deviceId);
                 if (log.isDebugEnabled()) {
                     log.debug(deviceId + " data has been fetched from " + deviceDAODefinition.getDeviceTableName() +
                             " database.");