Add jenkins-jobs command line tool.

So that jenkins-jobs can be easily run for testing from the source
dir without installation.

Change-Id: Iabba59ad32ccd4b79eb8934e53c6d747110a06b0
Reviewed-on: https://review.openstack.org/26259
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Monty Taylor <mordred@inaugust.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Tested-by: Jenkins