updated restore backup warning message and changed archive.Extract to ignore irregular files

tools/archive/create_test.go

@@ -48,7 +48,7 @@ func TestCreateSuccess(t *testing.T) {
 		t.Fatalf("Expected zip with name %q, got %q", zipName, name)
 	}
 
-	expectedSize := int64(405)
+	expectedSize := int64(544)
 	if size := info.Size(); size != expectedSize {
 		t.Fatalf("Expected zip with size %d, got %d", expectedSize, size)
 	}
@@ -116,5 +116,10 @@ func createTestDir(t *testing.T) string {
 		f.Close()
 	}
 
+	// symbolic link
+	if err := os.Symlink(filepath.Join(dir, "test"), filepath.Join(dir, "test_symlink")); err != nil {
+		t.Fatal(err)
+	}
+
 	return dir
 }