s3-spoolss: implement spoolss_EnumJobs level 3.

s3-spoolss: implement spoolss_EnumJobs level 3.

Level 3 has been added with NT 4.0 and Windows 7 (at least 64bit version) makes
use of it in order to display queued jobs. Windows 7 will *not* fall back to
level 2 if we just return WERR_UNKNOWN_LEVEL, instead there will be no printjobs
displayed at all.

Guenther
(cherry picked from commit 25001bbd1b0b32073073dab7cf5b78a2b902163f)
(cherry picked from commit eacb3b7be16884bb6bfcc3b4db97708566d66c40)

Fix bug #7130 (enumjobs level 3 is required by win7).