RFR: 1148: Emails on mailing lists are not posted to GitHub PR

[Erik Joelsson]

For a bit over a month, the mlbridge bot seems to be having trouble posting emails as comments in PRs. Especially the hotspot-dev list has been experiencing this. This patch should fix that problem.

The reading of the mailing list archives happens in MailmanListReader::conversations. There we loop over mailing lists and months. If a particular archive file (combo of mailing list and month) does not exist, the inner loop breaks. This break is the bug. In our case, the mailing list ide-support-dev does not have any emails for August and (I think because of that) the URL https://mail.openjdk.java.net/pipermail/ide-support-dev/2021-August.txt returns 404. This is triggering the break, which is stopping the inner loop (which loops over mailing lists) so it never gets to hotspot-dev (and a few others).

Looking at the history, this broke in SKARA-843, where the inner loop was added. The break statements then started acting on the wrong loop.

I'm also improving some log messages which I needed while debugging this.

-------------

Commit messages:
 - SKARA-1148

Changes: https://git.openjdk.java.net/skara/pull/1212/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1212&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1148
  Stats: 16 lines in 3 files changed: 0 ins; 3 del; 13 mod
  Patch: https://git.openjdk.java.net/skara/pull/1212.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1212/head:pull/1212

PR: https://git.openjdk.java.net/skara/pull/1212