Disable concurrent execution for push-upstream jobs

Parallel push from nordix can triggered a race condition in
upstream gerrit that will resulted in a duplicated review
instead of a single review for the first push and the second push.

Change-Id: I613531329aa4185d3f21f1c42c8d031e6cf95b4e
5 files changed
tree: da4fc42b67ee4d695bac57b7b804a75920775da0
  1. jjb/
  2. .gitignore
  3. .gitreview