libvirt.test: Improve virsh console test for lxc

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
libvirt.test: Improve virsh shutdown test for lxc

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
libvirt.tests: libvirt.test: Improve virsh reboot test for lxc

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>