fix pdml bug after or expansion transformation

src/sql/optimizer/ob_explain_note.h

@@ -36,6 +36,7 @@ namespace sql
 #define DIRECT_MODE_INSERT_INTO_SELECT  "Direct-mode is enabled in insert into select"
 #define PARALLEL_DISABLED_BY_DBLINK  "Degree of Parallelisim is %ld because stmt contain dblink which force das scan"
 #define PDML_DISABLED_BY_INSERT_PK_AUTO_INC "PDML disabled because the insert statement primary key has specified auto-increment column"
+#define PDML_DISABLED_BY_TRANSFORMATIONS "PDML disabled because transformations like or-expansion"
 
 }
 }