[Integrated] RFR: Avoid posting integrated notices for old RFR threads

[Robin Westberg]

Changeset: 364d5fb6
Author:    Robin Westberg <rwestberg at openjdk.org>
Date:      2020-04-28 04:44:29 +0000
URL:       https://git.openjdk.java.net/skara/commit/364d5fb6

Avoid posting integrated notices for old RFR threads

Reviewed-by: ehelin

! bots/mlbridge/src/main/java/org/openjdk/skara/bots/mlbridge/ReviewArchive.java
! bots/mlbridge/src/test/java/org/openjdk/skara/bots/mlbridge/MailingListBridgeBotTests.java