### Describe the issue

Restarting bitcoin, mempool starts filling from scratch.

### Can you reliably reproduce the issue?
#### If so, please list the steps to reproduce below:
1. Wait for mempool to reach for example 3000 transactions
2. Restart bitcoin
3. Watch mempool filling slowly from scratch

### Expected behaviour
Mempool would already contain ~3000 TX on startup

### Actual behaviour
It starts at 0 and fills up slowly with a few per second.

### Screenshots.
http://imgur.com/a/or82d

### What version of bitcoin-core are you using?
Windows x64 0.14rc1 binary from https://bitcoin.org/bin/bitcoin-core-0.14.0/test.rc1/


### Any extra information that might be useful in the debugging process.
I may not be aware of how the mempool.dat thing works and there could just be a misunderstanding.

}
                
                
                
            }
        } else { 
            assert(setBlockIndexCandidates.count(pindex) == 0);
        }
        
        std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeUnlinked = mapBlocksUnlinked.equal_range(pindex->pprev);
        bool foundInUnlinked = false;
        while (rangeUnlinked.first != rangeUnlinked.second) {
            assert(rangeUnlinked.first->first == pindex->pprev);
            if (rangeUnlinked.first->second == pindex) {
                foundInUnlinked = true;
                break;
            }
            rangeUnlinked.first++;
        }
        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed != NULL && pindexFirstInvalid == NULL) {
            
            assert(foundInUnlinked);
        }
        if (!(pindex->nStatus & BLOCK_HAVE_DATA)) assert(!foundInUnlinked); 
        if (pindexFirstMissing == NULL) assert(!foundInUnlinked); 
        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == NULL && pindexFirstMissing != NULL) {
            
            assert(fHavePruned);