Adjust overlay tests to expect "index=off"

When running tests on any modern distro, this assumption will work. If
we need to make it work with kernels where we don't append this option
it will require some more involved changes.

Signed-off-by: Phil Estes <[email protected]>
(cherry picked from commit 85d9fe3)
Signed-off-by: Akihiro Suda <[email protected]>

snapshots/overlay/overlay_test.go

@@ -174,6 +174,7 @@ func testOverlayOverlayMount(t *testing.T, newSnapshotter testsuite.SnapshotterF
 		lower = "lowerdir=" + getParents(ctx, o, root, "/tmp/layer2")[0]
 	)
 	for i, v := range []string{
+		"index=off",
 		work,
 		upper,
 		lower,
@@ -334,12 +335,12 @@ func testOverlayView(t *testing.T, newSnapshotter testsuite.SnapshotterFunc) {
 	if m.Source != "overlay" {
 		t.Errorf("mount source should be overlay but received %q", m.Source)
 	}
-	if len(m.Options) != 1 {
-		t.Errorf("expected 1 mount option but got %d", len(m.Options))
+	if len(m.Options) != 2 {
+		t.Errorf("expected 1 additional mount option but got %d", len(m.Options))
 	}
 	lowers := getParents(ctx, o, root, "/tmp/view2")
 	expected = fmt.Sprintf("lowerdir=%s:%s", lowers[0], lowers[1])
-	if m.Options[0] != expected {
+	if m.Options[1] != expected {
 		t.Errorf("expected option %q but received %q", expected, m.Options[0])
 	}
 }