switch certguard to store SSL certs entirely in the database
Core recently switched to storing all certs in the DB as TextFields and pulp-certguard should do the same.
It's not a safe assumption that a ssl cert can be placed on the filesystem, the user uses the API. Also keeping them on the filesystem could be less safe for something so sensitive. Typically databases are kept securely in one place, versus filesystems which in Pulp's case are typically shared.