AttentionSetEmail: Use fromChangeUpdateAndReason to generate messageId

This make the messageId generation consistent with how the messageId is
generated in EmailReviewComments.

Signed-off-by: Edwin Kempin <ekempin@google.com>
Release-Notes: skip
Change-Id: I8ed34f11dfe73195a9eea8001a0db1a5ea8568c9
diff --git a/java/com/google/gerrit/server/util/AttentionSetEmail.java b/java/com/google/gerrit/server/util/AttentionSetEmail.java
index 0699fde..1b36139 100644
--- a/java/com/google/gerrit/server/util/AttentionSetEmail.java
+++ b/java/com/google/gerrit/server/util/AttentionSetEmail.java
@@ -77,7 +77,8 @@
     MessageId messageId;
     try {
       messageId =
-          messageIdGenerator.fromChangeUpdate(ctx.getRepoView(), change.currentPatchSetId());
+          messageIdGenerator.fromChangeUpdateAndReason(
+              ctx.getRepoView(), change.currentPatchSetId(), "AttentionSetEmail");
     } catch (IOException e) {
       throw new UncheckedIOException(e);
     }