Comment 2 for bug 842178

StacktraceTop:
 g_variant_unref (value=0x0) at /build/buildd/glib2.0-2.29.18/./glib/gvariant-core.c:617
 g_settings_get_string (settings=<optimized out>, key=<optimized out>) at /build/buildd/glib2.0-2.29.18/./gio/gsettings.c:1770
 ffi_call_unix64 () at ../src/x86/unix64.S:75
 ffi_call (cif=0x7fff2d11db20, fn=0x7f552ec69b80 <g_settings_get_string>, rvalue=<optimized out>, avalue=<optimized out>) at ../src/x86/ffi64.c:486
 _g_callable_info_invoke (info=<optimized out>, function=0x7f552ec69b80, in_args=0x2366410, n_in_args=2, out_args=0x0, n_out_args=0, return_value=0x7fff2d11dcc0, is_method=1, throws=0, error=0x7fff2d11dcd8) at girepository/gicallableinfo.c:518