r2569: Patch from Rob Foehl <rwf@loonybin.net>:
- fix typo in libads/ldap_printer.c:39, ads_find_printer_on_server()
(originally libads-typo.patch)
- fix leak in printing/nt_printing.c, is_printer_published()
(originally is_printer_published-leak.patch)
- fix double print_backend_init() calls, now only called from main()
- restructuring in printing/nt_printing.c
- replaced (un)publish_it() with ads-specific functions
- moved common code to nt_printer_publish()
- improved error handling in several places
- added check_published_printers() in printing/nt_printing.c, to verify
that each published printer is actually in the directory at startup
- changed calling semantics of mod_a_printer, dump_a_printer, and
update_driver_init to be more consistent with the rest of the api and
reduce some copying