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-144/2019-04-24-0023/flakey.log

The failure seems to be in the "samba-ad-dc-2" suite, whose build logs are available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2019-04-24-0023/samba-ad-dc-2.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-144/2019-04-24-0023/samba-ad-dc-2.stdout
  
The top commit at the time of the failure was:

commit 76967b33ebb93a7ef5daa94b123ef9bfdce59ece
Author: Douglas Bagnall <douglas.bagnall at catalyst.net.nz>
Date:   Fri Apr 12 15:00:20 2019 +1200

    pyldb: avoid segfault when adding an element with no name
    
    We don't want to see this:
    
    python3 -c "import sys
    sys.path.insert(0, 'bin/python')
    import ldb
    m = ldb.Message()
    e = ldb.MessageElement('q')
    try:
        m.add(e)
    except ldb.LdbError:
        pass
    print(m)
    "
    Segmentation fault (core dumped)
    
    instead we want this:
    
    Traceback (most recent call last):
    File "<string>", line 7, in <module>
    ValueError: The element has no name
    
    Signed-off-by: Douglas Bagnall <douglas.bagnall at catalyst.net.nz>
    Reviewed-by: Noel Power <npower at samba.org>
    
    Autobuild-User(master): Noel Power <npower at samba.org>
    Autobuild-Date(master): Tue Apr 23 19:03:35 UTC 2019 on sn-devel-144

and the last 50 lines of the stdout log were:

[ 902/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_mul_d.c
[ 903/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_div_d.c
[ 904/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_sqr.c
[ 905/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_mod.c
[ 906/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_add_d.c
[ 907/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_div.c
[ 908/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_mul.c
[ 909/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_karatsuba_sqr.c
[ 910/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c
[ 911/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_karatsuba_mul.c
[ 912/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_add.c
[ 913/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_s_mp_sqr.c
[ 914/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_s_mp_mul_high_digs.c
[ 915/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_fast_s_mp_sqr.c
[ 916/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_fast_s_mp_mul_digs.c
[ 917/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_s_mp_mul_digs.c
[ 918/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_fast_s_mp_mul_high_digs.c
[ 919/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_s_mp_sub.c
[ 920/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_lshd.c
[ 921/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_cmp_d.c
[ 922/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_rshd.c
[ 923/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_exch.c
[ 924/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_init_size.c
[ 925/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_neg.c
[ 926/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_cmp_mag.c
[ 927/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_cmp.c
[ 928/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_copy.c
[ 929/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_init_copy.c
[ 930/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_abs.c
[ 931/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_init_set.c
[ 932/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_zero.c
[ 933/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_set.c
[ 934/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_set_int.c
[ 935/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_to_signed_bin_n.c
[ 936/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_zero_multi.c
[ 937/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_to_unsigned_bin_n.c
[ 938/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_grow.c
[ 939/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_shrink.c
[ 940/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_clamp.c
[ 941/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_prime_rabin_miller_trials.c
[ 942/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_invmod_slow.c
[ 943/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_init_set_int.c
[ 944/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bncore.c
[ 945/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_clear.c
[ 946/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_is_square.c
[ 947/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_get_int.c
[ 948/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_init.c
[ 949/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_sqrt.c
[ 950/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_exteuclid.c
[ 951/4195] Compiling source4/heimdal/lib/hcrypto/libtommath/bn_mp_prime_random_ex.c