BZ #1130304 - nfs-utils should be installed before using nfs

https://bugzilla.redhat.com/show_bug.cgi?id=1130304

Make sure nfs-utils is installed and the selinux bit flipped (if
applicable) before attempting to nfs mount something in glance or
cinder.
The contain keyword only works with classes, whereas the above is a resource type, so I don't think it it would work.  In theory, calling contain the class that contains cinder::backend::nfs, but tbh I'd rather not iterate/test on a non-functional change.