get buildmaster config synced up with the corresponding git repo

[warner]

Currently the tahoe buildmaster config has diverged from the git repo that's supposed to contain it. Fix this, and nail down a workflow to make it less likely to happen in the future.

[warner]

The buildmaster config is now mirrored to ​https://github.com/tahoe-lafs/buildbot-config-tahoe , and my (noisy but effective) workflow is to modify master.cfg on my local machine, commit, push to github, then pull from github down to org.

Bad properties of this workflow:

• I wind up committing syntax errors and other mistakes, because I can't use buildbot checkconfig to test my changes before committing
• I compare git hashes before restarting the buildmaster, but if I didn't, then github would have the opportunity to tamper with the config.

Sometimes I use a different workflow: edit on org, test in-place, commit (using an alias in the buildmaster account named git-commit-warner which adds --author), then push to github (there's a "deploy key" configured to enable org to push to github). This fixes both of the bad properties above, at the expense of being slightly more annoying (using emacs remotely, over TRAMP, is slow).

Anyways, we're in sync now, and there's at least one functional workflow to stay that way, so I'm closing this one.