Update default pool/path in pam_zfs_key.c

[eborisch]

While rpool is the default name throughout OpenZFS codebase -- in comments and tests, primarily -- this instance directly impacts the ease of use of pam_zfs_key, improving POLA.

With this change, the default value for the pam_zfs_key paramater homes=... matches what bsdinstall (https://cgit.freebsd.org/src/tree/usr.sbin/bsdinstall/scripts/zfsboot#n44) creates by default on a zfs install: zroot/home.

[bsdimp]

Sorry for the long delay. I think the best way forward is to submit it upstream, #ifdef'd for FreeBSD, and we'll bring it into the tree that way. Once it's upstreamed, we'll figure out the best way to land it.

[bsdimp]

Ping? What's the status of this upstream?

[eborisch]

Ping? What's the status of this upstream?

Sorry; out of sight, out of mind... I'll try to do this and link back.

[eborisch]

Fiinally got back to this and submitted an upstream PR. https://github.com/openzfs/zfs/pull/17600

[bsdimp]

Fiinally got back to this and submitted an upstream PR. openzfs/zfs#17600

Thanks