Add logDone logs where it's missing

Signed-off-by: Alexandr Morozov <lk4d4math@gmail.com>

integration-cli/docker_cli_diff_test.go

@@ -88,4 +88,6 @@ func TestDiffEnsureOnlyKmsgAndPtmx(t *testing.T) {
 			t.Errorf("'%s' is shown in the diff but shouldn't", line)
 		}
 	}
+
+	logDone("diff - ensure that only kmsg and ptmx in diff")
 }