Increase the build parallelism to 4

So far the CI has been quite happy to manage up to 3 parallel
changes validation. Let's try to see if we can pump up to 4
which means > 16 concurrent builds.

Change-Id: Iacabab406b52578dcdcbfdc4f1bb77dc41cd82b9
1 file changed
tree: 297e6a50abdca2a0e364a4e089f1c3fd325436df
  1. jenkins/
  2. jenkins-docker/
  3. .gitignore