Remove `lb` component from `jenkins.sh`

This commit removes the `lb` component from the Jenkins file as we do not need
to load-balance requests to/from the off-site backup machines. Therefore,
removing the `lb` component will ensure that we don't run this automatically
(and run in to errors, given that the lb.rb file does not exist in this
repository) when the job is Jenkinsified and run automagically.