Clear an old pass on a wait, and say a change of waits (review of #78)

A resource that passed, then waited, then failed once after its grace was
still stated healthy from the old pass; and a change of what it waits for
alone raised no change event, so the controller could miss it.

internal/liveness/liveness.go

@@ -368,7 +368,8 @@ func (j *Judge) Look(ctx context.Context) (Statement, bool) {
 		seen[r.ID] = true
 		st.Resources = append(st.Resources, State{Resource: k.Resource, State: k.State, Reason: k.Reason, Since: k.Since,
 			Streak: k.Streak, Restarts: k.Counted, Waits: waitsOf(k)})
-		word := k.State + "/" + k.Reason
+		// What it waits for is part of what is said: a change of waits alone is a change.
+		word := k.State + "/" + k.Reason + "/" + waitsWord(waitsOf(k))
 		if j.said[r.ID] != word {
 			changed = true
 			j.said[r.ID] = word
@@ -579,3 +580,12 @@ func waitsOf(k *kept) []health.Wait {
 	}
 	return append([]health.Wait(nil), k.Waits...)
 }
+
+// waitsWord is a resource's waits in one comparable word.
+func waitsWord(ws []health.Wait) string {
+	var b strings.Builder
+	for _, w := range ws {
+		b.WriteString(w.Part + "|" + w.Secret + "|" + w.Setting + "|" + w.What + ";")
+	}
+	return b.String()
+}