Awood/build gutterball

This PR should allow you to build in mock environments for both EL 6 and 7.  However, first you must install a recently built candlepin-common RPM.

```sh
$ cd common
$ tito build --test --builder mock --arg mock=candlepin-1-rhel-7-x86_64 --test --rpm --arg speedup
$ mock -r candlepin-1-rhel-7-x86_64 --install /tmp/tito/candlepin-common*.el7.noarch.rpm
$ cd ../gutterball
$ tito build --test --builder mock --arg mock=candlepin-1-rhel-7-x86_64 --test --rpm --arg speedup
```