### 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.

bool fEnforceBIP30 = (!pindex->phashBlock) || 
                          !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256S("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) ||
                           (pindex->nHeight==91880 && pindex->GetBlockHash() == uint256S("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721")));
    
    
    
    
    
    
    CBlockIndex *pindexBIP34height = pindex->pprev->GetAncestor(chainparams.GetConsensus().BIP34Height);
    
    fEnforceBIP30 = fEnforceBIP30 && (!pindexBIP34height || !(pindexBIP34height->GetBlockHash() == chainparams.GetConsensus().BIP34Hash));
    if (fEnforceBIP30) {
        for (const auto& tx : block.vtx) {
            const CCoins* coins = view.AccessCoins(tx->GetHash());
            if (coins && !coins->IsPruned())
                return state.DoS(100, error("ConnectBlock(): tried to overwrite transaction"),
                                 REJECT_INVALID, "bad-txns-BIP30");
        }
    }
    
    int64_t nBIP16SwitchTime = 1333238400;
    bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
    unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
    
    if (pindex->nHeight >= chainparams.GetConsensus().BIP66Height) {
        flags |= SCRIPT_VERIFY_DERSIG;
    }