add jenkins-build script

Move our Jenkins build script out of Jenkins' database and into Git so
that we can have greater visibility on future changes.

Going forward, we will modify the ceph-deploy Jenkins task to only run
this script.

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>
jenkins: write trace output to STDOUT

Add shell command tracing to the Jenkins build task.

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>
jenkins: remove commented GNUPGHOME

This is a legacy setting that we can simply remove from the script.

Signed-off-by: Ken Dreyer <ken.dreyer@inktank.com>
Merge pull request #149 from kdreyer-inktank/jenkins

migrate Jenkins build steps to Git