you mised one more parameter
var ODataModel = Model.extend("sap.ui.model.odata.ODataModel", /** @lends sap.ui.model.odata.ODataModel.prototype */ {
-? (sServiceUrl, true, null, null, null, false, true ???????? )
constructor : function(sServiceUrl, bJSON, sUser, sPassword, mHeaders, bTokenHandling, bWithCredentials, bLoadMetadataAsync) {
that's why we use json settings
sServiceUrl, {
...
loadMetadataAsync : true,
....
}