routing+routerrpc: remove probability estimates from mc state snapshot

Probability estimates are amount dependent. Previously we assumed an
amount, but that starts to make less sense when we make probability more
dependent on amounts in the future.

routing/missioncontrol_test.go

@@ -172,10 +172,6 @@ func TestMissionControl(t *testing.T) {
 
 	// Check whether history snapshot looks sane.
 	history := ctx.mc.GetHistorySnapshot()
-	if len(history.Nodes) != 1 {
-		t.Fatalf("unexpected number of nodes: expected 1 got %v",
-			len(history.Nodes))
-	}
 
 	if len(history.Pairs) != 3 {
 		t.Fatalf("expected 3 pairs, but got %v", len(history.Pairs))