Remove DOS from unconnecting thinblock
Remove DOS from unconnecting thinblock

This is not necessarily a misbehavior and can be treated like
an out of order header.

Bitcoin-com/BUcash,BitcoinUnlimited/BitcoinUnlimited,Justaphf/BitcoinUnlimited,Justaphf/BitcoinUnlimited,Bitcoin-com/BUcash,BitcoinUnlimited/BitcoinUnlimited,Bitcoin-com/BUcash,Justaphf/BitcoinUnlimited,Bitcoin-com/BUcash,Bitcoin-com/BUcash,Bitcoin-com/BUcash,BitcoinUnlimited/BitcoinUnlimited,BitcoinUnlimited/BitcoinUnlimited,Justaphf/BitcoinUnlimited,BitcoinUnlimited/BitcoinUnlimited,Justaphf/BitcoinUnlimited,BitcoinUnlimited/BitcoinUnlimited,Justaphf/BitcoinUnlimited