Bugfix: Autocreate IDP private key also if file exists but is empty

[wkloucek]

Description

Bugfix: Autocreate IDP private key also if file exists but is empty

We've fixed the behavior for the IDP private key generation so that
a private key is also generated when the file already exists but is empty.

Related Issue

• Boostrap issues on continously deployed oCIS demo instances

Motivation and Context

Somehow the IDP`s private-key.pem ends up as empty file after initalization. Therefore oCIS is stuck in a reboot loop sometimes.
If the private-key.pem is empty we can safely just overwrite it to prevent the reboot loop.

How Has This Been Tested?

• rm private-key.pem from the IDP data directory and create a empty file instead. oCIS from master does not start. oCIS from this PR will start just fine.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests only (no source changes)

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation ticket raised:

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.