Shared folder is not required for tests.
We should avoid hitting the error :
```
uninitialized constant VagrantPlugins::ProviderLibvirt::Action::ShareFolders
```
Also, disabling it might reduce the needed time in certains cases for the VMs
to be started.
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
If two environments are using the same subnet, we will get trouble
because of ips addresses conflicts.
This commit ensures each scenario has a uniq subnet for both public and cluster
network so we can setup several test environment at a time on a same hypervisor.
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>