Check Netpyne step in Guided Tour

[pgleeson]

The file here: https://docs.opensourcebrain.org/OSBv2/Guided_tour.html#create-a-network-simulation-using-netpyne is missing:

/home/jovyan/netpyne/workspace/OSBv2 Showcase/main/NetPyNE/HHTut/HHTut_data.json