Prevent jobs from overriding jobs in other repos

To avoid the situation where a job defined in a central config repo
is altered by a job definition in a project repo, or worse, two
project repos define jobs with the same name, add the restrition that
all variants of a job (ie, job definitions with the same name) must
be defined in the same repo.

Change-Id: I5d0004ff84fa5150edbb76f7f74920ab91c6cebb
3 files changed