dump: fix a bug that wrong table type is dumped

It is caused by the following conditions:

  * Table type is TABLE_PAT_KEY
  * Key is reference type

This fix the following test failure:

    [3] table/patricia_trie
      reference_key                                                 0.0368s [failed]
    ================================================================================
    --- (expected)
    +++ (actual)
    @@ -4,5 +4,5 @@
     [[0,0.0,0.0],true]
     dump
     table_create Names TABLE_PAT_KEY ShortText
    -table_create Users TABLE_PAT_KEY Names
    +table_create Users TABLE_HASH_KEY Names