Log docker machine IP address
When using auto-scaling this will print to stdout and syslog following message:
at the start:
Starting docker-machine build... build=1840675 created=2016-06-16 12:46:07.165254115 +0200 CEST docker=tcp://107.170.102.232:2376 name=runner-e0089f1d-kamil-auto-scale-runners-1466013997-901c5a03 project=100 runner=e0089f1d usedcount=0
and at the end:
Finished docker-machine build: exit code 129 build=1840675 created=2016-06-16 12:46:07.165254115 +0200 CEST docker=tcp://107.170.102.232:2376 name=runner-e0089f1d-kamil-auto-scale-runners-1466013997-901c5a03 project=100 runner=e0089f1d usedcount=0
This fixes: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/issues/1391
cc @tmaczukin