worksforme on Debian (GNUTLS 2.12.16-1).

Interpreting your log: StatusChanged to CONNECTING because REQUESTED, then Gabble crashes. ${builddir}/tests/twisted/tools/gabble-testing.log and/or backtrace from the core dump, please?

#0  0x00007fa85d16ee18 in g_logv (log_domain=0x7fa85d1ebd25 "GLib", log_level=G_LOG_LEVEL_WARNING, format=0x7fa85d1f13fc "%s", 
    args1=0x7fffb5e2d9c8) at gmessages.c:758
        domain = 0x0
        data = 0x0
        depth = 1
        log_func = 0x43e461 <log_handler>
        domain_fatal_mask = 5
        masquerade_fatal = 0
        test_level = 18
        was_fatal = 0
        was_recursion = 0
        i = 4
#1  0x00007fa85d16ef0c in g_log (log_domain=0x7fa85d1ebd25 "GLib", log_level=G_LOG_LEVEL_WARNING, format=0x7fa85d1f13fc "%s")
    at gmessages.c:792
        args = {{gp_offset = 24, fp_offset = 48, overflow_arg_area = 0x7fffb5e2daa0, reg_save_area = 0x7fffb5e2d9e0}}
#2  0x00007fa85d16f0b3 in g_warn_message (domain=0x7fa85d1ebd25 "GLib", file=0x7fa85d1ebd1c "gerror.c", line=390, 
    func=0x7fa85d1ebeb0 "g_error_new_valist", warnexpr=0x7fa85d1ebd10 "domain != 0") at gmessages.c:825
        s = 0x1c98c50 "(gerror.c:390):g_error_new_valist: runtime check failed: (domain != 0)"
        lstr = "390\000\000\000\000\000\034\275\036]\250\177\000\000%\275\036]\250\177\000\000\020\275\036]\250\177\000"
#3  0x00007fa85d14ed4a in g_error_new_valist (domain=0, code=0, format=0x54f38e "%d: %s", args=0x7fffb5e2dba0) at gerror.c:390
        error = 0x7fa85d459000
        __PRETTY_FUNCTION__ = "g_error_new_valist"
#4  0x00007fa85d14f186 in g_set_error (err=0x7fffb5e2dcc0, domain=0, code=0, format=0x54f38e "%d: %s") at gerror.c:560
        new = 0x0
        args = {{gp_offset = 32, fp_offset = 48, overflow_arg_area = 0x7fffb5e2dc80, reg_save_area = 0x7fffb5e2dbc0}}
#5  0x00000000004b246c in wocky_tls_set_error (error=0x7fffb5e2dcc0, result=-9) at wocky-tls.c:313
        code = -9
#6  0x00000000004b250e in wocky_tls_job_make_result (job=0x1c511d8, result=-9) at wocky-tls.c:341
        simple = 0x1cb1c60
        error = 0x0
        __PRETTY_FUNCTION__ = "wocky_tls_job_make_result"
#7  0x00000000004b2643 in wocky_tls_job_result_boolean (job=0x1c511d8, result=-9) at wocky-tls.c:387
        simple = 0x1c512c0
#8  0x00000000004b27e7 in wocky_tls_session_try_operation (session=0x1c51180, operation=WOCKY_TLS_OP_READ) at wocky-tls.c:421
        result = -9
        __PRETTY_FUNCTION__ = "wocky_tls_session_try_operation"
#9  0x00000000004b439a in wocky_tls_session_read_ready (object=0x1c692b0, result=0x1ca7460, user_data=0x1c51180) at wocky-tls.c:1179
        session = 0x1c51180
        __PRETTY_FUNCTION__ = "wocky_tls_session_read_ready"
---Type <return> to continue, or q <return> to quit---
#10 0x00007fa85db22323 in async_ready_callback_wrapper (source_object=0x1c692b0, res=0x1ca7460, user_data=0x1c51180)
    at ginputstream.c:470
        stream = 0x1c692b0
#11 0x00007fa85db3b93e in g_simple_async_result_complete (simple=0x1ca7460) at gsimpleasyncresult.c:744
        current_source = 0x1f1b000
        current_context = 0x1c3ad70
        __PRETTY_FUNCTION__ = "g_simple_async_result_complete"
#12 0x00007fa85db47ca7 in g_socket_input_stream_read_ready (socket=0x1cb0d40, condition=G_IO_IN, stream=0x1c692b0)
    at gsocketinputstream.c:166
        simple = 0x1ca7460
        error = 0x0
        result = 0
#13 0x00007fa85db40f83 in socket_source_dispatch (source=0x1f1b000, callback=0x7fa85db47b93 <g_socket_input_stream_read_ready>, 
    user_data=0x1c692b0) at gsocket.c:3142
        func = 0x7fa85db47b93 <g_socket_input_stream_read_ready>
        socket_source = 0x1f1b000
        socket = 0x1cb0d40
        ret = 0
#14 0x00007fa85d1652d3 in g_main_dispatch (context=0x1c3ad70) at gmain.c:2510
        dispatch = 0x7fa85db40ef9 <socket_source_dispatch>
        was_in_call = 0
        user_data = 0x1c692b0
        callback = 0x7fa85db47b93 <g_socket_input_stream_read_ready>
        cb_funcs = 0x7fa85d457b40
        cb_data = 0x1c7ddb0
        need_destroy = 29594160
        current_source_link = {data = 0x1f1b000, next = 0x0}
        source = 0x1f1b000
        current = 0x1c47630
        i = 0
        __PRETTY_FUNCTION__ = "g_main_dispatch"
#15 0x00007fa85d165f94 in g_main_context_dispatch (context=0x1c3ad70) at gmain.c:3047
No locals.
#16 0x00007fa85d166177 in g_main_context_iterate (context=0x1c3ad70, block=1, dispatch=1, self=0x1c33730) at gmain.c:3118
        max_priority = 2147483647
        timeout = -1
        some_ready = 1
        nfds = 6
        allocated_nfds = 6
---Type <return> to continue, or q <return> to quit---
        fds = 0x1c8b140
#17 0x00007fa85d1665a0 in g_main_loop_run (loop=0x1c3fe00) at gmain.c:3312
        self = 0x1c33730
        __PRETTY_FUNCTION__ = "g_main_loop_run"
#18 0x00007fa85df9ebff in tp_run_connection_manager (prog_name=<optimized out>, version=<optimized out>, construct_cm=<optimized out>, 
    argc=<optimized out>, argv=<optimized out>) at run.c:285
        connection = 0x1c37f00
        bus_daemon = 0x1c3c890
        error = 0x0
        ret = 1
        __PRETTY_FUNCTION__ = "tp_run_connection_manager"
#19 0x000000000043e6de in gabble_main (argc=1, argv=0x7fffb5e2e1a8) at gabble.c:182
        loader = 0x1c33860
        out = 0
        fatal_mask = 29
#20 0x0000000000431e1f in main (argc=1, argv=0x7fffb5e2e1a8) at main-debug.c:70
        ret = 1
        kludged = 0x1c34800

Created attachment 57389 [details]
logs

It was a Wocky bug. Fixed in git for 0.15.4