One trip to fix bug

## vector out of order in column reader

occur when use multiple ledger for column;

通过打印日志发现问题在于server，

server side problem: when multiple read request comes, the first finished ( while this is not the expected oldest) will return quickly.

maybe the entryQueue is out of order, true

solution:  two methods below:

1. check wantted , request list to keep order

2. use hash-like container to contain entry(cacheEntry )

the easier way is to sequencially check read future.