public-inbox-ssoma fails with lkml archive

[Yaron Scheffer <yscheffer@protonmail.com>]

Hi. I've been trying to get ssoma to fetch LKML archives into my mailbox using
the git repo at `https://lore.kernel.org/lkml/6`. Running `ssoma sync` shows
the git fetch completing successfully, but nothing shows up in my Maildir.
Performing the same procedure does however work with the PI archive at `git
://public-inbox.org/meta`.

My perl was rusty 15 years ago and it hasn't gotten any better with time,
but I've debugged this a little and the gittish things in Extractor.pm
led me to what looks like a smoking gun:

On the clone of git://public-inbox.org/meta:

    # git log --name-only
    commit 0fc21086aabb4ff9e9318a8ec3c6b58b24e9618a (HEAD -> master)
    ...
    c7/16e8798bc662c5fb52d05416a27897b49f0634

    commit d307195d89b21619de79722793cfaa7698aa5cf4
    ...
    99/a639f7c6842e6c69f489f9c60af1be5e3f152d

On the clone of https://lore.kernel.org/lkml/6:

    # git log --name-only
    commit fa44fffb6a81e1a6b9cceccf8c08074d4d5d83ca (HEAD -> master)
    ...
    m

    commit 9845bd1f6b14185eaa77eaceea212ee0d04da673
    ...
    m

so the lkml archive doesn't follow (mandatory, I presume) naming scheme as
PI/meta. I'm not sure if this is an issue in upstream or the deployment,
but right now ssoma doesn't work with the lkml archive.

Yaron