libcli/security: improve conditional ACE composite comparison

libcli/security: improve conditional ACE composite comparison

We had the comparison method wrong. Composites are compared as sets or
flabby sets, depending on their origin. Until now we compared them as
something a bit like sets, but not quite, in a maximally inefficient way.

Claims are always sets, and the left hand side is always a claim, but
literal composites on the right hand side can be multi-sets
(containing duplicate values). When it comes to comparison, composites
are reduced down to sets. To do the comparison we sort each side and
compare in order.

The fact that either side might ask for case-sensitive comparison (if
it is a claim) is an interesting complication.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>