Consider adding log message to VERSION.txt/New Relic/Flowdock

[xendk]

While sha uniquely identifies the deployed version, and the branch gives some indication too, the log message usually tells a human more.

But there's an disclosure of information issue here. Would we like the log message being, essentially, public information.

For New Relic it's a no-brainer, there's no reason not to add the log message. We should just skip messages starting with "Merged", or else they become a tad useless.

Flowdock might as well get all the log entries since the last deployment. It supports the extra text, and it'll mirror the new Github integration.