RPM Support

If a content unit exists on disk but is not on the DB, Pulp re-downloads the content at sync time.

Pulp should instead recognize that a rpm plugin unit (rpm, srpm, drpm, distribution) is on disk and use that to create the unit in the database from. The result would be that content which exists on disk is not re-downloaded.

Steps to Reproduce:
1. Sync a large repo
2. Watch it take a while
3. Clear your mongo db
4. rerun pulp-manage-db
5. Sync the same repo
6. Watch it take the same amount of time (all the files are on the file system, so it should take the same amount of time)