xfce4-panel: binary clock leaks memory
When adding a binary clock in non-"true binary" mode, the memory consumption of
xfce4-panel grows indefinitely.
It seems that this is due to
xfce_clock_binary_draw_binary missing a
g_date_time_unref (time); at the end.
I tested this on v4.14, but the bug seems to present all the way from 1e4d05c8 to current master.