Update configuration.py
Update AUTHORS
Merge branch 'pgustafs-1097816' of github.com:pgustafs/pulp_rpm into mhrivnak-1097816
1097816 - adding "gpgkey" as a valid distributor config value
Merge pull request #523 from pulp/mhrivnak-1097816

1097816 - adding "gpgkey" as a valid distributor config value