[Integrated] RFR: Improve merge bot commit message

[Jorn Vernee]

Changeset: 5c96b1cc
Author:    Jorn Vernee <jvernee at openjdk.org>
Date:      2020-02-05 14:46:59 +0000
URL:       https://git.openjdk.java.net/skara/commit/5c96b1cc

Improve merge bot commit message

Reviewed-by: ehelin

! bots/merge/src/main/java/org/openjdk/skara/bots/merge/MergeBot.java
! bots/merge/src/test/java/org/openjdk/skara/bots/merge/MergeBotTests.java