Avoid returning a BIP9Stats object with uninitialized values
Avoid returning a BIP9Stats object with uninitialized values

Uninitialized data potentially used in `rpc/blockchain.cpp`:

```
static UniValue BIP9SoftForkDesc(const Consensus::Params& consensusParams, Consensus::DeploymentPos id)
{
    ...
    const ThresholdState thresholdState = VersionBitsTipState(consensusParams, id);
    ...
    if (THRESHOLD_STARTED == thresholdState)
    {
        UniValue statsUV(UniValue::VOBJ);
        BIP9Stats statsStruct = VersionBitsTipStatistics(consensusParams, id);
        statsUV.push_back(Pair("period", statsStruct.period));
        statsUV.push_back(Pair("threshold", statsStruct.threshold));
        statsUV.push_back(Pair("elapsed", statsStruct.elapsed));
        statsUV.push_back(Pair("count", statsStruct.count));
        statsUV.push_back(Pair("possible", statsStruct.possible));
        rv.push_back(Pair("statistics", statsUV));
    }
    ...
    return rv;
}
```

Github-Pull: #10957
Rebased-From: 3eb53b867153c957529484b5338d27e69de027c1

wangxinxi/litecoin,BitzenyCoreDevelopers/bitzeny,gjhiggins/vcoincore,qtumproject/qtum,BitzenyCoreDevelopers/bitzeny,particl/particl-core,UFOCoins/ufo,BitzenyCoreDevelopers/bitzeny,GroestlCoin/GroestlCoin,tecnovert/particl-core,GroestlCoin/GroestlCoin,digibyte/digibyte,tecnovert/particl-core,qtumproject/qtum,digibyte/digibyte,GroestlCoin/bitcoin,Jcing95/iop-hd,Anfauglith/iop-hd,wangxinxi/litecoin,GroestlCoin/bitcoin,romanornr/viacoin,romanornr/viacoin,Anfauglith/iop-hd,BitzenyCoreDevelopers/bitzeny,romanornr/viacoin,GroestlCoin/bitcoin,GroestlCoin/bitcoin,UFOCoins/ufo,gjhiggins/vcoincore,qtumproject/qtum,tecnovert/particl-core,particl/particl-core,UFOCoins/ufo,BitzenyCoreDevelopers/bitzeny,tecnovert/particl-core,UFOCoins/ufo,particl/particl-core,GroestlCoin/GroestlCoin,GroestlCoin/bitcoin,gjhiggins/vcoincore,qtumproject/qtum,Anfauglith/iop-hd,tecnovert/particl-core,qtumproject/qtum,digibyte/digibyte,Jcing95/iop-hd,particl/particl-core,digibyte/digibyte,romanornr/viacoin,GroestlCoin/bitcoin,UFOCoins/ufo,wangxinxi/litecoin,gjhiggins/vcoincore,Jcing95/iop-hd,GroestlCoin/GroestlCoin,gjhiggins/vcoincore,digibyte/digibyte,qtumproject/qtum,BitzenyCoreDevelopers/bitzeny,particl/particl-core,Anfauglith/iop-hd,UFOCoins/ufo,Anfauglith/iop-hd,particl/particl-core,Jcing95/iop-hd,GroestlCoin/GroestlCoin,GroestlCoin/GroestlCoin,Jcing95/iop-hd,romanornr/viacoin,Jcing95/iop-hd,gjhiggins/vcoincore,romanornr/viacoin,digibyte/digibyte,Anfauglith/iop-hd,qtumproject/qtum,wangxinxi/litecoin,tecnovert/particl-core,wangxinxi/litecoin,wangxinxi/litecoin