Improve error logging on onehost sync

[OpenNebulaSupport]

Description
Provide clear error messages in case onehost sync fails to update hosts

-bash-4.2$ onehost sync --force
* Adding ord-virt-003 to upgrade
* Adding ord-virt-016 to upgrade
* Adding ord-virt-015 to upgrade
* Adding ord-virt-012 to upgrade
* Adding ord-virt-011 to upgrade
* Adding ord-virt-008 to upgrade
* Adding ord-virt-007 to upgrade
* Adding ord-virt-004 to upgrade
[========================================] 8/8 ord-virt-004
Failed to update the following hosts:
* ord-virt-016
* ord-virt-003
* ord-virt-012
* ord-virt-015
* ord-virt-008
* ord-virt-011
* ord-virt-007
* ord-virt-004

Use case
Easier troubleshooting

Additional Context
In this case the error was due to root permissions existing in a directory inside the remotes directory which is to be synced to the hosts.

ls /var/lib/one/remotes/
drwxr-x--- 8 oneadmin oneadmin 4.0K Jul 19 2021 etc/
drwxr-x--- 7 root root 4.0K Jan 29 2020 etc.2020-01-29/
drwxr-x--- 8 jsfrerot oneadmin 4.0K Feb 11 2020 etc.2021-05-12/    # <------------
drwxr-x--- 8 oneadmin oneadmin 4.0K Apr 22 2021 etc.2021-05-17/

Progress Status

• Code committed
• Testing - QA
• Documentation (Release notes - resolved issues, compatibility, known issues)

[tinova]

reference #6151

[tinova]

• Doc F OpenNebula/one#5906: Update resolved issues docs#2610