message: fix decode mysql field byte error
diff: @@ -505,7 +505,7 @@ static sw_inline int mysql_decode_field(char *buf, int len, mysql_field *col)
  i += 1;
  /* flags */
  - col->flags = mysql_uint3korr(&buf[i]);
  + col->flags = mysql_uint2korr(&buf[i]);
  i += 2;
  /* decimals */
  