[CBR-414] fix demo-nix.sh to have all core nodes working
[CBR-414] fix demo-nix.sh to have all core nodes working

input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype,input-output-hk/pos-haskell-prototype,input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/cardano-sl,input-output-hk/pos-haskell-prototype