[BUG] boot hang due to configuration 'error'

**Describe the bug**

Whilst investigating significantly slow boot times on a freshly installed Debian Buster VM that almost exclusively relate to WALinuxAgent, I've discovered what I hope is a bug and not a feature.

On changing the following config fragment from:

ResourceDisk.Format=y
ResourceDisk.EnableSwap=n
ResourceDisk.SwapSizeMB=4096

to:

ResourceDisk.Format=n
ResourceDisk.EnableSwap=n
ResourceDisk.SwapSizeMB=4096

I'm experiencing a boot hang which can clearly be observed via the serial console. And because the systemd unit waagent.service timeout is, understandably I suppose, set to infinity, said VM is now completely inaccessible, meaning I have to waste yet more time re-installing this particular VM.

Serial console screenshot:


Note: a stock /etc/waagent.conf as per that installed by waagent-2.2.26-1 should be all that's required to reproduce this; the only settings I changed are those resource disk-related ones as above.

**Distro and WALinuxAgent details (please complete the following information):**

Distro: Debian Buster
Agent: waagent-2.2.26-1

Am unsure at present whether this bug is also present in newer versions, I'll try and verify that once I've finished restoring the affected VM from backups...

Start by reproducing the boot hang on Debian Buster with the stated /etc/waagent.conf resource-disk settings, then inspect the waagent.service startup path and the serial-console output. Done means changing ResourceDisk.Format to n no longer leaves the VM inaccessible or causes the service to hang during boot.

Written by the indexing model from the issue text.