Use polymorphic variant to track gpumon's state
Use polymorphic variant to track gpumon's state

No semantic change, but the code should hopefully be a bit clearer.

Signed-off-by: John Else <37b74501daa612e48fea94f9846ed4ddeb6a8f07@citrix.com>

jjd27/xen-api,jjd27/xen-api,jjd27/xen-api,jjd27/xen-api,jjd27/xen-api,jjd27/xen-api