[FAB-4503] Disable brittle tests - deliveryService

1) Disable TestCloseWhileRecv as it sometimes times out
2) TestDisconnect - This test was merged today but it
   seems like it sometimes fails. Disabling for now, to investigate offline

Change-Id: I8e1b38b851d93512d2ea1c7925e5dc518987e76b
Signed-off-by: Yacov Manevich <yacovm@il.ibm.com>

core/deliverservice/client_test.go

@@ -471,6 +471,7 @@ func testGreenPath(t *testing.T, bdc blocksDelivererConsumer) {
 }
 
 func TestCloseWhileRecv(t *testing.T) {
+	t.Skip()
 	// Scenario: Recv is being called and after a while,
 	// the connection is closed.
 	// The Recv should return immediately in such a case
@@ -599,6 +600,7 @@ func TestProductionUsage(t *testing.T) {
 }
 
 func TestDisconnect(t *testing.T) {
+	t.Skip()
 	// Scenario: spawn 2 ordering service instances
 	// and a client.
 	// Have the client try to Recv() from one of them,