Do not count the machine's own plumbing mounted into a container as found data (hq ADR 0103)

internal/apply/hold_test.go

@@ -754,3 +754,20 @@ func TestAUserFoundOnTheMachineKeepsItsShellAndGroups(t *testing.T) {
 		}
 	}
 }
+
+func TestMountingTheMachinesOwnPlumbingIsNotFoundData(t *testing.T) {
+	// The runtime's socket, the kernel's filesystems and the clock are on every machine; a
+	// container mounting them shares nothing a predecessor kept (novox/hq ADR 0103).
+	dir := t.TempDir()
+	m := &machine{containers: map[string]*fakeContainer{}}
+	report, state := applyAdopted(t, adopted(t, untaken("hello-web.server"),
+		`{"id":"hello-web.server","type":"container","name":"hello-web","image":"`+pinned+`",
+		  "volumes":["/var/run/docker.sock:/var/run/docker.sock","/etc/localtime:/etc/localtime:ro",
+		             "/proc/cpuinfo:/host/cpuinfo:ro","/dev/null:/data/null"]}`), store.State{}, m, dir)
+	if o := outcomeOf(report, "hello-web.server"); o.Action != "created" {
+		t.Errorf("a container mounting only system paths was not created: %+v", o)
+	}
+	if len(state.Held) != 0 {
+		t.Errorf("held: %+v", state.Held)
+	}
+}