This adds checks whether each OpenVPN configuration section exists exactly once
and whether its begin comes before its end.

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>