remote-viewer: Extend #ifdef HAVE_OVIRT block
    
    The #endif is closing a #ifdef HAVE_OVIRT block, while another one is
    opened right next, so there is no need to have those lines. Also, due to
    the large amount of source code in between, add a small comment on the
    last #endif to identify what it refers to.
    
    Signed-off-by: Eduardo Lima (Etrunko) <etrunko@redhat.com>