Opening two of the same wallet (tested in v0.18.0 of bitcoin-qt 64 bit) will cause a database collision, and will crash the program.

`[marshall@likon] {21:21} [~] $ bitcoin-0.18.0/bin/bitcoin-qt `
`terminate called after throwing an instance of 'std::runtime_error'  what():  BerkeleyBatch: Can't open database 8204388-wallet.dat (duplicates fileid 8b1c090000000800e25686350000000000000000 from 1352491-wallet.dat)`
`Aborted (core dumped)`

I have been able to reproduce the issue by importing two of the same wallet (with different filenames).
{
    
    
    
    
    std::set<uint256> visited_spk_mans;
    for (unsigned int i = 0; i < tx.vin.size(); i++) {
        
        CTxIn& txin = tx.vin[i];
        auto coin = coins.find(txin.prevout);
        if (coin == coins.end() || coin->second.IsSpent()) {
            input_errors[i] = "Input not found or already spent";
            continue;
        }
        
        SignatureData sigdata = DataFromTransaction(tx, i, coin->second.out);
        if (sigdata.complete) {
            continue;
        }
        
        std::set<ScriptPubKeyMan*> spk_mans = GetScriptPubKeyMans(coin->second.out.scriptPubKey, sigdata);
        if (spk_mans.size() == 0) {
            input_errors[i] = "Unable to sign input, missing keys";
            continue;
        }
        for (auto& spk_man : spk_mans) {
            
            if (visited_spk_mans.count(spk_man->GetID()) > 0) {
                continue;
            }