s3-spoolss: fix printer_driver_files_in_use() call ordering
printer_driver_files_in_use() performs two tasks: it returns whether any
of the files in the to-be-deleted driver overlap with other drivers, it
also trims such files from the info structure passed in.
In processing a DeletePrinterDataEx request with DPD_DELETE_UNUSED_FILES
set, printer_driver_files_in_use() must be called to ensure files in
use by other drivers are not removed.
https://bugzilla.samba.org/show_bug.cgi?id=4942
Signed-off-by: Andreas Schneider <asn@samba.org>