QXmlQuery: percent sign gets encoded

use case:

evaluate xpath like
QXmlQuery query;
QString string("http://api.flickr.com/services/rest/?text=%1").arg(...);
query.setQuery(string);

Now when the text contains an ampersand ("&"), we need to encode it to "%26", otherwise the QXmlQuery will crash. But then internally the percent sign of "%26" will become encoded again.