manifests/key.pp: set also the file mode bits for keyring files

This should prevent other users beeing able to read and use
the keyring file to access the cluster.

Signed-off-by: Danny Al-Gaaf <d.al-gaaf@telekom.de>
Merge pull request #2 from TelekomCloud/hotfix/wip-da-fix-keyringfile-filemodebits

manifests/key.pp: set also the file mode bits for keyring files