message: refactor: change VList border from 1000 to
  1000 is just for test with lubm or bbug, is for real case
  by zengli, no changes to other modules
diff: @@ -35,8 +35,8 @@ class VList
  {
  public:
  //NOTICE:the border is 10^6, but the block is larger, 1M
  - //static const unsigned LENGTH_BORDER = 1000000;
  - static const unsigned LENGTH_BORDER = 1000;
  + static const unsigned LENGTH_BORDER = 1000000;
  + //static const unsigned LENGTH_BORDER = 1000;
  static const unsigned BLOCK_SIZE = 1 << 20; //fixed size of disk-block
  static const unsigned MAX_BLOCK_NUM = 1 << 23; //max block-num
  //below two constants: must can be exactly divided by 8
  