cgroups: reuse version check from c/common

[NO NEW TESTS NEEDED]

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

info.go

@@ -12,6 +12,7 @@ import (
 	internalUtil "github.com/containers/buildah/internal/util"
 	putil "github.com/containers/buildah/pkg/util"
 	"github.com/containers/buildah/util"
+	"github.com/containers/common/pkg/cgroups"
 	"github.com/containers/storage"
 	"github.com/containers/storage/pkg/system"
 	"github.com/containers/storage/pkg/unshare"
@@ -50,7 +51,7 @@ func hostInfo() map[string]interface{} {
 	info["cpus"] = runtime.NumCPU()
 	info["rootless"] = unshare.IsRootless()
 
-	unified, err := util.IsCgroup2UnifiedMode()
+	unified, err := cgroups.IsCgroup2UnifiedMode()
 	if err != nil {
 		logrus.Error(err, "err reading cgroups mode")
 	}

util/util.go

@@ -9,7 +9,6 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
-	"sync"
 	"syscall"
 
 	"github.com/containers/buildah/define"
@@ -376,12 +375,6 @@ func TruncateString(str string, to int) string {
 	return newStr
 }
 
-var (
-	isUnifiedOnce sync.Once
-	isUnified     bool
-	isUnifiedErr  error
-)
-
 // fileExistsAndNotADir - Check to see if a file exists
 // and that it is not a directory.
 func fileExistsAndNotADir(path string) (bool, error) {