s3-smbd: Remove sys_acl_*() VFS wrapper functions

s3-smbd: Remove sys_acl_*() VFS wrapper functions

We no longer do struct smb_acl_t manipuations via the VFS layer,
which is now reduced to handling the get/set functions.

The only backend that implemented these functions (aside from audit)
was the vfs_default module calling the sys_acl code.  The various ACL
implementation modules either worked on the fully initilaised
smb_acl_t object or on NT ACLs.

This not only makes the operation of the posix ACL code more efficient
(as allocation and free is not put via the VFS), it makes it easier to
test and removes the fantasy that a module could safely redefine this
structure or the behaviour here.

The smb_acls.idl now defines the structure, and it is now allocated
with talloc.

These operations were originally added to the VFS in commit
3bb219161a270f12c27c3bc7e1220829c6e9f284.

Andrew Bartlett