_active_mounts_openbsd: unbreak output for special filesystems
_active_mounts_openbsd: unbreak output for special filesystems

mount(8) output is a little bit different on OpenBSD between local and special
or remote filesystems (e.g. tmpfs or nfs). These do not use a UUID nor a device.

https://github.com/saltstack/salt/issues/34012

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt