daemon/events; fix TestLoadBufferedEventsOnlyFromPast

commit 70ad5b818fa94891d0778daba2f830e5ca6382a7 changed event.Type
to be a strong type, no longer an alias for string. for some reason,
this test passed on the PR, but failed later on;

    === Failed
    === FAIL: daemon/events TestLoadBufferedEventsOnlyFromPast (0.00s)
        events_test.go:203: assertion failed: network (messages[0].Type events.Type) != network (string)

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

daemon/events/events_test.go

@@ -200,7 +200,7 @@ func TestLoadBufferedEventsOnlyFromPast(t *testing.T) {
 
 	messages := evts.loadBufferedEvents(since, until, nil)
 	assert.Assert(t, is.Len(messages, 1))
-	assert.Check(t, is.Equal(messages[0].Type, "network"))
+	assert.Check(t, is.Equal(messages[0].Type, events.NetworkEventType))
 }
 
 // Regression-test for https://github.com/moby/moby/issues/13753