Manager.GetCircuit should work on an empty manager

[Jack Lindamood]

On an empty manager object, it should return nil

[Chris Vaughn]

I was looking at issues in this repo to contribute to. Either this isn't an issue any longer or this needs more info. There appears to be a test for this:

func TestManager_Empty(t *testing.T) {
	h := Manager{}
	if h.GetCircuit("does_not_exist") != nil {
		t.Error("found a circuit that does not exist")
	}
}

If I'm misunderstanding the issue and this needs work please let me know.

[Jack Lindamood]

Hmmm perfect! Thanks for catching this.