python/schema: fix tests flapping due to oid collision

python/schema: fix tests flapping due to oid collision

These tests would sometimes fail because the randomly generated OIDs
would collide. This fixes that by giving a unique OID to each attribute
and class.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=12507

Pair-Programmed-With: Bob Campbell <bobcampbell@catalyst.net.nz>

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Tue Jan 10 13:44:02 CET 2017 on sn-devel-144