libyang CHANGE review header includes

The plugins_types.h was supposed only for implementing data type plugins
code, so I've removed it from libyang.h (now it is supposed to be
included explicitly).
diff --git a/src/parser_xml.c b/src/parser_xml.c
index f3abaa4..20709b7 100644
--- a/src/parser_xml.c
+++ b/src/parser_xml.c
@@ -24,7 +24,7 @@
 #include "parser_data.h"
 #include "parser_internal.h"
 #include "set.h"
-#include "tree.h"
+#include "tree_data.h"
 #include "tree_data_internal.h"
 #include "tree_schema.h"
 #include "validation.h"