create attributes with null value for empty attribute nodes.

Original patch by milovanderlinden, simplified by tschaub. r=me
(closes #1556)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@9179 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Format/GML.js

@@ -558,6 +558,12 @@ OpenLayers.Format.GML = OpenLayers.Class(OpenLayers.Format.XML, {
                                                 this.regExes.trimSpace, "");
                                 attributes[name] = value;
                             }
+                        } else {
+                            // If child has no childNodes (grandchildren),
+                            // set an attribute with null value.
+                            // e.g. <prefix:fieldname/> becomes
+                            // {fieldname: null}
+                            attributes[child.nodeName.split(":").pop()] = null;
                         }
                     }
                 }