Only mount /vagrant/logs if not using NFS

The NFS configuration exports the vagrant root directory with user
mapping enabled. This allows the guest to mount the directory and write
to it using any user while the host sees the files as owned by the
configured map user.

Change-Id: Ic3e2620d259b4a81fee59b51e676c80f131b02fc
Merge "Only mount /vagrant/logs if not using NFS"