lxd/instance/drivers/driver/qemu: Logs when instance is stopped in getMonitorEventHandler
lxd/instance/drivers/driver/qemu: Logs when instance is stopped in getMonitorEventHandler

And removes some references to the instance in the function returned from getMonitorEventHandler so they are not kept in memory.

Signed-off-by: Thomas Parrott <6b778ce645fb0e3dde76d79eccad490955b1ae74@canonical.com>

stgraber/lxd,atxwebs/lxd,hallyn/lxd,hallyn/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,atxwebs/lxd,stgraber/lxd,lxc/lxd,stgraber/lxd,hallyn/lxd,lxc/lxd,atxwebs/lxd,hallyn/lxd,hallyn/lxd,lxc/lxd,lxc/lxd,lxc/lxd,stgraber/lxd,atxwebs/lxd