https://bugzilla.redhat.com/show_bug.cgi?id=905280
https://bugzilla.redhat.com/show_bug.cgi?id=967493

Sanlock expects that the configured kill script either kills the PID on
lock failure or removes all locks the PID owns. If none of the two
options happen, sanlock will reboot the host. Although IGNORE action is
supposed to ignore the request to kill the PID or remove all leases,
it's certainly not designed to cause the host to be rebooted. That said,
IGNORE action is incompatible with sanlock and should be forbidden by
libvirt.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>