virt-libvirt: add configuration for virsh reboot

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
virt-libvirt: add virsh function for virsh reboot

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

Signed-off-by: Li Yang <liyang.fnst@cn.fujitsu.com>
virt-libvirt: Minor fixups to virsh reboot test

* Added a verifyable default value for remote_ip/local_ip parameters
* Wraped two long lines
* Added a FIXME to catch-all 'except' statement
* Print out debugging info when there's a problem
* Add check for older libvirt version on command error

Signed-off-by: Chris Evich <cevich@redhat.com>