freight is failing to host ubuntu 18.04 packages. 

For the ubuntu 18.04 packages, the Packages.gz which gets generated is not proper. The parent package and dependent package versions are not listed in order, so the installation os parent package fails. For e.g `python` and `python-minimal` versions are not listed correctly. So when apt takes the first version that is listed for both, there'll be a mismatch. 
 