CentOS 7 and Scientific Linux 7 should also use systemd module
Merge pull request #13748 from simoncadman/develop

CentOS 7 and Scientific Linux 7 should also use systemd module
Fixing pylint violations
Update expected message
Add sock_dir to raet swarming
Add worker sleep betwen creation
Merge pull request #13764 from pass-by-value/more_test_fixes

Update expected message
clarifications to gce cloud docs
iraet swarm needs ports
Merge pull request #13765 from rallytime/gce_docs

clarifications to gce cloud docs
Merge pull request #13763 from nmadhok/fix-lint

Fixing pylint violations