Remove unused goog.require

Found by the latest version of closure-compiler (v20150729)

src/ol/format/wmsgetfeatureinfoformat.js

@@ -5,7 +5,6 @@ goog.require('goog.asserts');
 goog.require('goog.dom.NodeType');
 goog.require('goog.object');
 goog.require('goog.string');
-goog.require('ol.format.GML');
 goog.require('ol.format.GML2');
 goog.require('ol.format.XMLFeature');
 goog.require('ol.xml');