Fix TestGetAdditionalGroups on i686

Fixes: #941

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>

libcontainer/utils/utils.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"strings"
 	"syscall"
+	"unsafe"
 )
 
 const (
@@ -119,3 +120,7 @@ func Annotations(labels []string) (bundle string, userAnnotations map[string]str
 	}
 	return
 }
+
+func GetIntSize() int {
+	return int(unsafe.Sizeof(1))
+}