conf: Resolve Coverity FORWARD_NULL
    
    Even though it's been pointed out they are false positives:
    
    http://www.redhat.com/archives/libvir-list/2015-May/msg00301.html
    
    and
    
    http://www.redhat.com/archives/libvir-list/2015-May/msg00302.html
    
    these still show up as Coverity issues. In order to silence Coverity
    add an 'sa_assert' prior to check failure.
    
    Signed-off-by: John Ferlan <jferlan@redhat.com>