Improve prepare4image.sh using virt-sysprep as inspiration source

[cmd-ntrf]

RedHat has a tool named virt-sysprep that can "reset, unconfigure or customize a virtual machine so clones can be made".

It is meant to be executed on shutted down virtual machine and goes to some extents that are not required for MC, but it could be used an inspiration to make sure there is no blind spot left.

Someone has created a similar project for packer : https://github.com/DanHam/packer-virt-sysprep OCaml code of virt-sysprep operations : https://github.com/rwmjones/guestfs-tools/tree/master/sysprep

[cmd-ntrf]

virt-sysprep operations to review for applicability to prepare4image.sh:

• [x] ipa-client sysprep_operation_ipa_client.ml
• [x] kerberos-hostkeytab sysprep_operation_kerberos_hostkeytab.ml
• [ ] logfiles sysprep_operation_logfiles.ml
• [x] machine id - sysprep_operation_machine_id.ml
• [ ] mail-spool sysprep_operation_mail_spool.ml
• [x] net-hwaddr sysprep_operation_net_hwaddr.ml
• [x] package-manager-cache sysprep_operation_package_manager_cache.ml
• [ ] passwd-backup sysprep_operation_passwd_backups.ml
• [x] puppet-data-log sysprep_operation_puppet_data_log.ml
• [x] rpm-db sysprep_operation_rpm_db.ml
• [x] ssh-hostkeys sysprep_operation_ssh_hostkeys.ml
• [x] ssh-userdir sysprep_operation_ssh_userdir.ml
• [x] sssd-db-log sysprep_operation_sssd_db_log.ml
• [x] tmp-files sysprep_operation_tmp_files.ml
• [x] udev-persistent-net sysprep_operation_udev_persistent_net.ml
• [ ] ~**abrt-data*** sysprep_operation_abrt_data.ml~
• [ ] ~**backup-files*** sysprep_operation_backup_files.ml~
• [ ] ~bash-history sysprep_operation_bash_history.ml~
• [ ] ~blkid-tab sysprep_operation_blkid_tab.ml~
• [ ] ~ca-certificates sysprep_operation_ca_certificates.ml~
• [ ] ~crash-data sysprep_operation_crash_data.ml~
• [ ] ~cron-spool sysprep_operation_cron_spool.ml~
• [ ] ~customize sysprep_operation_customize.ml~
• [ ] ~dhcp-client-state sysprep_operation_dhcp_client_state.ml~
• [ ] ~dhcp-server-state sysprep_operation_dhcp_server_state.ml~
• [ ] ~dovecot-data sysprep_operation_dovecot_data.ml~
• [ ] ~firewall-rules sysprep_operation_firewall_rules.ml~
• [ ] ~flag-reconfiguration sysprep_operation_flag_reconfiguration.ml~
• [ ] ~fs-uuids sysprep_operation_fs_uuids.ml~
• [ ] ~kerberos-data sysprep_operation_kerberos_data.ml~
• [ ] ~lvm-system-devices sysprep_operation_lvm_system_devices.ml~
• [ ] ~lvm-uuids sysprep_operation_lvm_uuids.ml~
• [ ] ~net-hostname sysprep_operation_net_hostname.ml~
• [ ] ~net-nmconn sysprep_operation_net_nmconn.ml~
• [ ] ~pacct-log sysprep_operation_pacct_log.ml~
• [ ] ~pam-data sysprep_operation_pam_data.ml~
• [ ] ~rh-subscription-manager sysprep_operation_rh_subscription_manager.ml~
• [ ] ~rhn-systemid sysprep_operation_rhn_systemid.ml~
• [ ] ~samba-db-log sysprep_operation_samba_db_log.ml~
• [ ] ~script sysprep_operation_script.ml~
• [ ] ~smolt-uuid sysprep_operation_smolt_uuid.ml~
• [ ] ~user-account sysprep_operation_user_account.ml~
• [ ] ~utmp sysprep_operation_utmp.ml~
• [ ] ~yum-uuidsysprep_operation_yum_uuid.ml~