[Pacemaker] Advisory ordering and "Cannot migrate"

[Vladislav Bogdanov]

Hi Andrew, David, all,

It seems that advisory ordering is honored when pengine wants to move
two advisory-ordered resources in one transition, and one of resources
(then) is migrateable.

I have advisory ordering configured for two resources, "mgs" and
"drbd-testfs-stacked":

order drbd-testfs-stacked-after-mgs 0: mgs:start drbd-testfs-stacked:start

"mgs" is ordinary resource, "drbd-testfs-stacked" is migrateable.

If both that resources are located on one node, and I request shutdown
of that node, I see:
pengine[2069]:   notice: check_stack_element: Cannot migrate
drbd-testfs-stacked due to dependency on mgs (order)