Comment 2 for bug 724767

StacktraceTop:
 g_variant_is_trusted (value=0x0) at /build/buildd/glib2.0-2.28.1/./glib/gvariant-core.c:600
 g_variant_builder_add_value (builder=0x7fff0dc14f10, value=0x0) at /build/buildd/glib2.0-2.28.1/./glib/gvariant.c:3081
 g_variant_valist_new (str=0x7fff0dc14fc8, app=0x7fff0dc14ff0) at /build/buildd/glib2.0-2.28.1/./glib/gvariant.c:4093
 g_variant_new_va (format_string=0x4070fa ")", endptr=0x0, app=0x7fff0dc14ff0) at /build/buildd/glib2.0-2.28.1/./glib/gvariant.c:4248
 g_variant_builder_add (builder=0x7fff0dc150f0, format_string=<value optimized out>) at /build/buildd/glib2.0-2.28.1/./glib/gvariant.c:4390