[chef] Upgrade process

[Jeff Blaine < >]

I see that the wiki has information about upgrading from 0.9 to
0.10 and similar. Aside from that, the wiki's other information
on the topic is... less than encouraging.

Has anyone developed a workable upgrade process for minor[sic]
revisions? Care to share? Have we re-embraced bash + SSH in a
for-loop?