mediawiki.api: fix badtoken handling with legacy token types

mediawiki.api: fix badtoken handling with legacy token types

Manual test plan:

mw.loader.using( 'mediawiki.api.login' ).done( function () {
	var
		user = 'XXX',
		pass = 'YYY',
		api = new mw.Api();

	api.login( user, pass ).done( function () {
		api.postWithToken( 'options', {
			action: 'options',
			optionname: 'userjs-tokentest',
			optionvalue: 1
		} ).fail( function () {
			console.log( arguments );
		} );
	} );
} );

Change-Id: I175cf4e3a845cdfe621b6009920fddba6bc1ff12