Simplify default export

This removes unnecessary variable declarations where the default object is an object.

src/ol/format/IGCZ.js

@@ -1,14 +1,13 @@
 /**
  * @module ol/format/IGCZ
  */
+
 /**
  * IGC altitude/z. One of 'barometric', 'gps', 'none'.
  * @enum {string}
  */
-var _ol_format_IGCZ_ = {
+export default {
   BAROMETRIC: 'barometric',
   GPS: 'gps',
   NONE: 'none'
 };
-
-export default _ol_format_IGCZ_;