vcldir_retire() only sends a VCL_EVENT_COLD when the vcl is warm. In
other words, it (rightly) asserts that a COLD event (if any) has
alrady been posted when a director is deleted on a COLD vcl.

Yet, when the director is deleted upon a COLD vmod event, this assertion
was wrong, because the COLD events for directors were only posted after
vmod events.

Given that vmods do things like deleting directors, it appears (more)
correct to post VDI COLD events before VMOD COLD events.