Fix errors reported by golangci-lint
golangci-lint run kernel/permission/acl
kernel/permission/acl/ak_2_account.go:88:16: Error return value of `json.Unmarshal` is not checked (errcheck)
json.Unmarshal(aclJSON, acl)
^
kernel/permission/acl/ak_2_account.go:101:2: unreachable: unreachable code (govet)
return nil
^