BUGFIX: update the same value, row affect is not zero. reserved_random assignment in JsonBinHeader.

deps/oblib/src/lib/json_type/ob_json_bin.h

@@ -70,6 +70,15 @@ typedef struct ObJsonBinKeyDict {
 } ObJsonBinKeyDict;
 
 typedef struct ObJsonBinHeader {
+  ObJsonBinHeader()
+  : type_(0), 
+        entry_size_(0), 
+        count_size_(0), 
+        obj_size_size_(0), 
+        is_continuous_(0), 
+        reserved_(0) 
+  {
+  }
   uint8_t type_;			 // node type for current node
   uint8_t entry_size_   : 2; // the size describe var size of key_entry, val_entry
   uint8_t count_size_   : 2; // the size describe var size of element count