execute user-del pre-callback also during user preservation
user preservation code was not using the pre-callback function which did check
whether a protected member is being deleted and facilitated the
orphaning/deletion of OTP tokens owner/managed by the user.
https://fedorahosted.org/freeipa/ticket/5362https://fedorahosted.org/freeipa/ticket/5372
Reviewed-By: Tomas Babej <tbabej@redhat.com>