Use /etc/crowbar/network.json as path for network configuration

This is a change in SUSE Cloud 2.0, where we don't want to change the
template files.
Merge pull request #5 from vuntz/network-json-path

Use /etc/crowbar/network.json as path for network configuration
- Use /etc/crowbar/network.json as path for network configuration
- 2.27.30