Collapse a few boolean operations

internal/archiver/archiver_test.go

@@ -1458,10 +1458,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 				"other": TestFile{Content: "another file"},
 			},
 			selFn: func(item string, fi os.FileInfo) bool {
-				if filepath.Ext(item) == ".txt" {
-					return false
-				}
-				return true
+				return filepath.Ext(item) != ".txt"
 			},
 		},
 		{
@@ -1485,10 +1482,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 				"other": TestFile{Content: "another file"},
 			},
 			selFn: func(item string, fi os.FileInfo) bool {
-				if filepath.Base(item) == "subdir" {
-					return false
-				}
-				return true
+				return filepath.Base(item) != "subdir"
 			},
 		},
 		{

internal/walker/walker.go

@@ -84,7 +84,7 @@ func walk(ctx context.Context, repo restic.TreeLoader, prefix string, parentTree
 				return false, err
 			}
 
-			if ignore == false {
+			if !ignore {
 				allNodesIgnored = false
 			}