always forceflush stale data (not just based on statsevery)

[JamieDanielson]

It seems like we should move the flush logic outside of the if block, similar to how done is outside the if block but logs based on the statsevery config option.

	flushed, closed := h.assembler.FlushCloseOlderThan(time.Now().Add(-h.config.Timeout))
	if count%h.config.Statsevery == 0 {

Originally posted by @JamieDanielson in #94 (comment)