Fix invalid cast to CTransaction* in WalletModelTransaction
Fix invalid cast to CTransaction* in WalletModelTransaction

CWalletTx/CMerkleTx does not derive from CTransaction anymore.
This code is different in Bitcoin as it was touched by SegWit code,
resulting in an upfront fix.

ivansib/sibcoin,crowning-/dash,biblepay/biblepay,dashpay/dash,nmarley/dash,biblepay/biblepay,ionomy/ion,biblepay/biblepay,ionomy/ion,UdjinM6/dash,thelazier/dash,UdjinM6/dash,crowning-/dash,biblepay/biblepay,crowning-/dash,ionomy/ion,dashpay/dash,crowning-/dash,dashpay/dash,thelazier/dash,nmarley/dash,nmarley/dash,ionomy/ion,nmarley/dash,nmarley/dash,thelazier/dash,dashpay/dash,biblepay/biblepay,crowning-/dash,ionomy/ion,ivansib/sibcoin,ivansib/sibcoin,ivansib/sibcoin,ivansib/sibcoin,UdjinM6/dash,nmarley/dash,dashpay/dash,crowning-/dash,biblepay/biblepay,biblepay/biblepay,thelazier/dash,UdjinM6/dash,nmarley/dash,thelazier/dash,ivansib/sibcoin,biblepay/biblepay,ionomy/ion,UdjinM6/dash