v.io/jiri/util: use runutil.Sequence.

Change-Id: Ifd748e60b45f1aa2afa10d79f63b14fa72022268
diff --git a/util/config.go b/util/config.go
index 9268b83..3870052 100644
--- a/util/config.go
+++ b/util/config.go
@@ -291,7 +291,7 @@
 }
 
 func loadConfig(jirix *jiri.X, path string) (*Config, error) {
-	configBytes, err := jirix.Run().ReadFile(path)
+	configBytes, err := jirix.NewSeq().ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
@@ -398,10 +398,9 @@
 	if err != nil {
 		return fmt.Errorf("MarshalIndent(%v) failed: %v", data, err)
 	}
-	if err := jirix.Run().MkdirAll(filepath.Dir(path), os.FileMode(0755)); err != nil {
-		return err
-	}
-	if err := jirix.Run().WriteFile(path, bytes, os.FileMode(0644)); err != nil {
+	s := jirix.NewSeq()
+	if err := s.MkdirAll(filepath.Dir(path), os.FileMode(0755)).
+		WriteFile(path, bytes, os.FileMode(0644)).Done(); err != nil {
 		return err
 	}
 	return nil
diff --git a/util/oncall_test.go b/util/oncall_test.go
index a1b3eca..a2c9893 100644
--- a/util/oncall_test.go
+++ b/util/oncall_test.go
@@ -42,7 +42,7 @@
 	}
 	dir := filepath.Dir(oncallRotationsFile)
 	dirMode := os.FileMode(0700)
-	if err := jirix.Run().MkdirAll(dir, dirMode); err != nil {
+	if err := jirix.NewSeq().MkdirAll(dir, dirMode).Done(); err != nil {
 		t.Fatalf("MkdirAll(%q, %v) failed: %v", dir, dirMode, err)
 	}
 	fileMode := os.FileMode(0644)