Reading /sys/devices/system/cpu/online makes opening the cpu
directories unnecessary and works on more/older systems.
Signed-off-by: NJanosch Frank <frankja@linux.vnet.ibm.com>
Message-Id: <1452525484-32309-21-git-send-email-frankja@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>