Fix cyclic package reporting

I don't think closed pull requests can be re-opened? But it's alright because https://github.com/ros-infrastructure/catkin_pkg/pull/89 included changes meant for another pull request anyways.

This fixes bug https://github.com/ros-infrastructure/catkin_pkg/issues/92

See previous discussion in https://github.com/ros-infrastructure/catkin_pkg/pull/89 which was closed although the alternative change did not fix the real problem (which, to be fair, wasn't articulated in a bug).