Medium: VirtualDomain: support more virsh domstate output formats

Some virsh versions use lower-case for messages, some use upper-case for domstate output. In order to account for this, convert to lowercase before parsing.
Also take into account "failed to connect to hypervisor" next to "failed to reconnect to hypervisor"
Merge pull request #363 from liedekef/patch-2

Medium: VirtualDomain: support more virsh domstate output formats