Handle IDMAP_BOTH in posix_acls.c

[Andrew Bartlett]

In my s3-acls branch I have a patch to use IDMAP_BOTH in posix_acls.c

I know you are both very keen to get IDMAP_BOTH properly supported in
smbd, so we can support GPOs in the s3fs configuration.  I'm hoping to
today and tomorrow write some tests for GPO ACLs but in the meantime I
think this is what we need:
https://git.samba.org/?p=abartlet/samba.git/.git;a=commitdiff;h=9ae38a8f985bf04c598ab8b469226fe94e2624a5

It passes a manual autobuild.

BTW, for testing I was planning on writing a python script to:
 - reading the DS ACLs from LDB
 - write local xattr values
 - reading back over SMB
 - write over SMB
 - read over SMB

Hopefully this will closely enough emulate the GPO behaviour we need to
test. 

Andrew Bartlett
-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org