Add --1.x option for Crowbar 1.x (Pebbles)

This patch is needed to assemble a working Crowbar 1.x (eg. Pebbles) branch into a single Git repository, so we can more easily run the code analysis (eg. brakeman, tailor) and tests.

**Update:** We're already using this code in our [public Jenkins server](http://ci.opensuse.org/view/Crowbar/job/crowbar-pebbles-travis_ci-trackupstream/) to merge Pebbles (Crowbar 1.6) into a single Git repository. This in turn triggers the [Pebbles Travis CI](https://travis-ci.org/crowbar/travis-ci-crowbar/branches) job.