build: Write -buildresult.json file containing exact revisions
build: Write -buildresult.json file containing exact revisions

This records the exact revisions resulting from a particular build; at
present, the latest.

GNOME/gnome-ostree,chergert/gnome-continuous,djdeath/gnome-ostree,GNOME/gnome-ostree,djdeath/gnome-ostree,vrutkovs/vrutkovs.github.io,GNOME/gnome-ostree,chergert/gnome-continuous,djdeath/gnome-ostree,vrutkovs/vrutkovs.github.io,vrutkovs/vrutkovs.github.io,chergert/gnome-continuous