Re-fix bug 5202 - cannot change ACLs on writable file with "dos filemode=yes"

Re-fix bug 5202 - cannot change ACLs on writable file with "dos filemode=yes"

This bug re-occurred for 3.3.x and above.

The reason is that to change a NT ACL we now have to open the file requesting
WRITE_DAC and WRITE_OWNER access. The mapping from POSIX "w" to NT permissions
in posix_acls doesn't add these bits when "dos filemode = yes", so even though
the permission or owner change would be allowed by the POSIX ACL code, the
NTCreateX call fails with ACCESS_DENIED now we always check NT permissions
first.

Added in the mapping from "w" to WRITE_DAC and WRITE_OWNER access.

Jeremy.