High: PE: Bug cl#5028 - Unmanaged services should block shutdown unless in maintainence mode

'Unmanaged' in this context means failed with on-fail=block.

Not doing this could lead to services being active in more than one location
as the node is considered safely stopped.

Resources that are configured to be unmanaged will not block shutdown
/unless/ there is another resource that cannot shutdown until the
unmanaged one has - since that is impossible.