Description of problem: Right now the removal of the prefix from a filepath is done server-side, which isn't right now that the prefix can be set from the rhn-download-manager client.
I moved the prefix-removing code from the server to the client and changed the client so the prefix entered by the user will always end in a "/", even if they didn't enter it on the command-line.
Mass move to ON_QA
PROD_READY with the other rhn-download-manager bug.