[Bug] Build timeout

Created by: juadde

Describe the bug Build does not finish anymore with latest changes.

To Reproduce Steps to reproduce the behavior:

1. Fetch latest master branch
2. run packer build -only=virtualbox-iso local.json or packer build cloud.json
3. Wait for ssh_timeout to end (> 2h)
4. Build does not finish

Expected behavior Build should finish successfully.

Screenshots & Logs VM does not restart, even if "systemctl reboot" is sent to the machine. The VMs is stuck here:

Packer finishes with the following error:

Build 'virtualbox-iso' errored: Timeout waiting for SSH. ==> Some builds didn't complete successfully and had errors: --> virtualbox-iso: Timeout waiting for SSH. ==> Builds finished but no artifacts were created.

Host Software (please complete the following information):

• OS: Windows / Linux
• Distribution: 10 Pro / Archlinux
• Vagrant Version: 2.2.7
• Packer: 1.5.4
• Hypervisor: Virtualbox
• Hypervisor Version: 6.1.4
• Image Version: Current master branch
• Output of uname -a: N/A
• Vagrant Plugins: vagrant-reload (0.0.1, global), vagrant-timezone (1.3.0, global), vagrant-vbguest (0.20.0, global), vagrant-windows-update (0.0.7, global), vagrant_reboot_linux (1.0.0, global)

Additional context Build is successful on those machines before the changes for the cloud scripts (Rebuilding the arch-box from an older commit is working properly). I will investigate to get the exact commit where the build begin to fail and report here: ea7869f1 is working properly.

Please let me know if anybody have a clue on what is happening.