After trying to figure out what was going on, the response to a simple sanity check command said it all:
+ git config --list --global fatal: $HOME not set
More details filed here: https://issues.jenkins-ci.org/browse/JENKINS-4046
In my case the debian package was slightly newer (the one that came with Ubuntu 11.10), and jenkins is now controlled using
service, and i modified the
/etc/init/jenkins file to include
env HOME="/var/lib/jenkins"with the rest of the environment variables.