Rewrote the iso export distributor
Merge branch 'pulp-2.2.1' into jcline-rpm-iso-export
make sure the relative path for a repo is actually relative
Addressed issues in PR review
fixed documentation and the file_descriptor now uses its write method
Reverted file descriptor handling and added unit key to rpm metadata
Merge branch 'pulp-2.2.1' into jcline-rpm-iso-export
Merge pull request #283 from pulp/jcline-rpm-iso-export

rewrote the rpm export distributor