tests: Remove redundant lxc test
    
    This test was added in 2d40e2da7ba to ensure LXC domains could be
    defined correctly when caps probing was skipped due to SKIP_OSTYPE.
    However we do caps probing unconditionally now, so this test case
    is redundant
    
    Acked-by: Michal Privoznik <mprivozn@redhat.com>
    Signed-off-by: Cole Robinson <crobinso@redhat.com>