[Rest Server] Update priority class owner references

[abuccts]

Update priority class owner references to avoid foreground deletion errors.

[yqwang-ms]

This is a workaround to resolve GC controller hang in "Namespace parameter required" due to not support cross namespaced refer:

E1107 08:26:09.488367       1 garbagecollector.go:310] error syncing item &garbagecollector.node{
identity:garbagecollector.objectReference{
	OwnerReference:v1.OwnerReference{
		APIVersion:"frameworkcontroller.microsoft.com/v1", 
		Kind:"Framework", 
		Name:"edqqexbyedqqexazc8wkacv2ccrp8", 
		UID:"d19d8fd9-f93f-11e9-a441-000d3ab408a6", 
		Controller:(*bool)(0xc000ad0a78), 
		BlockOwnerDeletion:(*bool)(0xc000ad0a79)
	}, 
	Namespace:""
}, 
dependentsLock:sync.RWMutex{w:sync.Mutex{state:0, sema:0x0}, writerSem:0x0, readerSem:0x0, readerCount:1, readerWait:0}, 
dependents:map[*garbagecollector.node]struct {}{(*garbagecollector.node)(0xc00118e690):struct {}{}}, 
deletingDependents:false, deletingDependentsLock:sync.RWMutex{w:sync.Mutex{state:0, sema:0x0}, writerSem:0x0, readerSem:0x0, readerCount:0, readerWait:0}, 
beingDeleted:false, beingDeletedLock:sync.RWMutex{w:sync.Mutex{state:0, sema:0x0}, writerSem:0x0, readerSem:0x0, readerCount:0, readerWait:0}, 
virtual:false, 
virtualLock:sync.RWMutex{w:sync.Mutex{state:0, sema:0x0}, writerSem:0x0, readerSem:0x0, readerCount:0, readerWait:0}, 
owners:[]v1.OwnerReference(nil)}: Namespace parameter required.

Note: Cross-namespace owner references are disallowed by design. This means: 1) Namespace-scoped dependents can only specify owners in the same namespace, and owners that are cluster-scoped. 2) Cluster-scoped dependents can only specify cluster-scoped owners, but not namespace-scoped owners.

https://kubernetes.io/docs/concepts/workloads/controllers/garbage-collection/

In future, we should customize queuing order by scheduler framework, instead of per job priority class object.