Comment 2 for bug 760536

StacktraceTop:
 currency_get_value (currency=0x0) at currency.c:75
 unit_convert_from (unit=<value optimized out>, x=0x7fffbebc47b0, z=<value optimized out>) at unit.c:141
 unit_category_convert (category=<value optimized out>, x=<value optimized out>, x_units=<value optimized out>, z_units=0xab9000, z=0x7fffbebc2860) at unit-category.c:100
 update_result_label (converter=0x813dc0) at math-converter.c:72
 g_closure_invoke (closure=0xab1520, return_value=0x0, n_param_values=1, param_values=0xf8ef80, invocation_hint=0x7fffbebc68c0) at /build/buildd/glib2.0-2.28.5/./gobject/gclosure.c:767