hammer2 - Enhance pfs-list and pfs-delete
* Enhance pfs-list to list PFSs available across all mounted hammer2
filesystems instead of just the current directory's mount. A
specific mount may be specified via -s mountpt.
* Enhance pfs-delete to look for the PFS name across all mounted
hammer2 filesystems instead of just the current directory's mount.
As a safety, pfs-delete will refuse to delete PFS names which are
duplicated across multiple mounts. A specific mount may be specified
via -s mountpt.