When validating secure guests support on s390(x) we may read
/proc/cmdline and look for "prot_virt" argument. Reading the
kernel command line is done via virFileReadValueString() which
may fail. In such case caller won't see any error message. But we
can produce the same warning/error as if "prot_virt" argument
wasn't found. Not only this lets users know about the problem,
it also terminates the "Checking for ...." line correctly.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Fabiano Fidêncio <fabiano@fidencio.org>