Add a recursiveGit step
Add a recursiveGit step

This step does a git checkout recursively and accept also
to specify the refspec to fetch (which the default jenkins
git step does not allow).

Change-Id: If873d23eb264f3993059bd93d76868e75fffd0cb

bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration