autobuild[sn-devel-144]: intermittent test failure detected

[autobuild]

The autobuild test system (on sn-devel-144) has detected an intermittent failing test in 
the current master tree.

The autobuild log of the failure is available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-08-02-1851/flakey.log

The failure seems to be in the "samba-none-env" suite, whose build logs are available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-08-02-1851/samba-none-env.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-08-02-1851/samba-none-env.stdout
  
The top commit at the time of the failure was:

commit e053aad4ae46dfcda6143d55e8e913e923fa34be
Author: Noel Power <noel.power at suse.com>
Date:   Thu Jun 28 16:04:24 2018 +0100

    s3/utils: fix regression where specifying -Unetbios/root works
    
    Usually you need to be root on a linux server to modify quotas. Even
    with a linux server joined to a windows AD you could always log in as
    local root with smbcquotas. However in recent builds this has changed.
    This patch fixes this
    
    BUG: https://bugzilla.samba.org/show_bug.cgi?id=13553
    
    Signed-off-by: Noel Power <noel.power at suse.com>
    Reviewed-by: Jeremy Allison <jra at samba.org>
    
    Autobuild-User(master): Noel Power <npower at samba.org>
    Autobuild-Date(master): Tue Jul 31 19:45:59 CEST 2018 on sn-devel-144

and the last 50 lines of the stdout log were:

[215(3123)/247 at 19m36s] pidl.samba3-srv
[216(3124)/247 at 19m36s] pidl.tdr
[217(3130)/247 at 19m36s] pidl.test_util
[218(3136)/247 at 19m36s] pidl.typelist
[219(3192)/247 at 19m37s] pidl.util
[220(3264)/247 at 19m38s] pidl.wireshark-conf
[221(3313)/247 at 19m39s] pidl.wireshark-ndr
[222(3353)/247 at 19m40s] tdb.python
[223(3407)/247 at 19m41s] samba.tests.dsdb_lock
[224(3414)/247 at 20m52s] samba.tests.samba_tool.visualize
[225(3425)/247 at 20m55s] samba.tests.samba_tool.provision_password_check
[226(3429)/247 at 21m3s] samba.tests.samba_tool.help
[227(3430)/247 at 21m40s] samba.tests.loadparm
[228(3433)/247 at 21m40s] samba4.blackbox.samba3dump
[229(3434)/247 at 21m40s] samba4.blackbox.upgrade
[230(3442)/247 at 22m5s] samba4.blackbox.provision.py
[231(3449)/247 at 22m51s] samba4.blackbox.supported_features
[232(3455)/247 at 23m0s] samba4.blackbox.start_backup
[233(3458)/247 at 23m8s] samba4.blackbox.upgradeprovision.current
[234(3465)/247 at 24m27s] samba4.blackbox.setpassword.py
[235(3471)/247 at 24m37s] samba4.blackbox.newuser.py
[236(3482)/247 at 24m49s] samba4.blackbox.group.py
[237(3511)/247 at 25m6s] samba4.blackbox.provision-backend
[238(3515)/247 at 25m13s] samba4.blackbox.renamedc.sh
[239(3526)/247 at 25m35s] samba4.dsdb.samdb.ldb_modules.unique_object_sids
[240(3532)/247 at 25m35s] samba4.dsdb.samdb.ldb_modules.encrypted_secrets
[241(3543)/247 at 25m35s] lib.audit_logging.audit_logging
[242(3558)/247 at 25m35s] lib.audit_logging.audit_logging.errors
[243(3572)/247 at 25m35s] samba4.dsdb.samdb.ldb_modules.audit_util
[244(3589)/247 at 25m35s] samba4.dsdb.samdb.ldb_modules.audit_log
UNEXPECTED(failure): samba4.dsdb.samdb.ldb_modules.audit_log.test_operation_json_empty(none)
REASON: Exception: Exception: o
../source4/dsdb/samdb/ldb_modules/tests/test_audit_log.c:333: error: Failure!

FAILED (1 failures, 0 errors and 0 unexpected successes in 0 testsuites)

A summary with detailed information can be found in:
  ./bin/ab/summary
TOP 10 slowest tests
samba.tests.docs -> 174
samba.tests.docs.python3 -> 164
samba4.blackbox.upgradeprovision.release-4-0-0 -> 116
samba4.blackbox.upgradeprovision.alpha13 -> 114
samba4.blackbox.schemaupgrade -> 108
samba4.blackbox.upgradeprovision.current -> 78
samba.tests.dsdb_lock -> 71
samba4.blackbox.dbcheck.release-4-0-0 -> 66
samba4.blackbox.dbcheck.release-4-1-0rc3 -> 56
samba4.blackbox.functionalprep -> 52
ERROR: test failed with exit code 1