Comment 3 for bug 1389287

So we may need to do next here:
1. If test destroy nailgun container - we receive exception and it is expected, so you need to implement some kind of exception - then catch it and copy and tar /var/log directory (or may be invoke shotgun to generate snapshot)
2. for case when admin node installation fail - we should use libguestfs to extract the log data (we have separate issue for this case)