s/any_priv_below/any_privs_below/ for consistency and switch from a
single &str for the path param to the slice-ref string variant, as
that allows to use it more often without allocation.
Also allow passing the whole path as single &str element in the slice
by splitting each component on '/' like we do in other parts
nowadays. Note though that we need to omit the leading slash then.
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>