Change the permissible minimum value of nodesuspend duration time
to 60 seconds. If option is less than the value, reports error.
Update virsh help and manpage the infomation.
Commands in host group moved from virsh.c to virsh-host.c,
* virsh.c: Remove commands in host group.
* virsh-host.c: New file, filled with commands in host group
* po/POTFILES.in: Add virsh-host.c
* cfg.mk: Skip to check config.h including for virsh-host.c