Fix cdata construction without libxml2 headers
The argument order for `Nokogiri::XML::CDATA::new` and
`Nokogiri::XML::Text::new` are swapped.
@@ -62,7 +62,7 @@ static VALUE create_internal_subset;
#define xmlNewDocText(doc, text) \
rb_funcall(Text, new, 2, rb_str_new2(text), doc)
#define xmlNewCDataBlock(doc, content, length) \
- rb_funcall(CDATA, new, 2, rb_str_new(content, length), doc)
+ rb_funcall(CDATA, new, 2, doc, rb_str_new(content, length))
#define xmlNewDocComment(doc, text) \
rb_funcall(Comment, new, 2, doc, rb_str_new2(text))
#define xmlAddChild(element, node) \
