Brad King authored Dec 09, 2015 and Ben Boeckel committed Sep 07, 2017

Store the upstream commit sha1 in the upstream snapshot commit message
subject line.  Format the subject line to make it easy to find the most
recent snapshot commit in history to use as the base for the next
update.

In order to help transition existing scripts, take the basehash from
them for now and allow an empty update commit.