Fix bug 9900: is_printer_published GUID retrieval
Samba currently always responds to GetPrinter(level = 7) requests with
DSPRINT_UNPUBLISH, regardless of the AD publish status tracked via the
PRINTER_ATTRIBUTE_PUBLISHED flag. This is due to erroneous "objectGUID"
unmarshalling in is_printer_published().
This change splits "objectGUID" retrieval into a separate function, and
adds a pull_reg_sz() call to correctly unmarshall the GUID.
Signed-off-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>