The following folders are required for the nova proposal on ubuntu.

* /var/cache/nova/
* /var/lib/nova/.ssh/

Signed-off-by: JuanJose 'JJ' Galvez <jj.galvez@inktank.com>
When creating the SSH key we need to specify the shell
otherwise /bin/false is used and creation fails.

Signed-off-by: JuanJose 'JJ' Galvez <jj.galvez@inktank.com>