some small fix for 'run_pylint.py libvirt/tests/'

(1).Lots of 'Too long line'
(2).Some exception type.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>

mv domblkinfo from virsh_cmd/domain to virsh_cmd/monitor.

This test was commited after new structure of libvirt
virsh_cmd. But it should be added into virsh_cmd/monitor,
not virsh_cmd/domain.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>