Description of problem:
The UI checks for valid urls but the API does not.  The UI does not handle this condition when syncing.

Version-Release number of selected component (if applicable):
katello-0.1.70-1.git.288.120a626.fc14.noarch

How reproducible:


Steps to Reproduce:
1. Create a product
2. In that product, use the API to create a repo with blank URL (nil).
3. In the GUI, sync the product
  
Actual results:
Fails silently

Expected results:
Fails with error message in the UI about what's wrong with that repo

Additional info:
Logs:

RestClient::NotAcceptable (Pulp::Repository: 406 Not Acceptable "Repo [1314294222681-testrepo-1314294224019-ACME_Corporation] is not setup for sync. Please add packages using upload." (POST /pulp/api/repositories/1314294222681-testrepo-1314294224019-ACME_Corporation/sync/)):
  lib/http_resource.rb:94:in `post'
  lib/resources/pulp.rb:205:in `sync'
  app/controllers/sync_management_controller.rb:173:in `sync_repos'
  app/controllers/sync_management_controller.rb:170:in `each'
  app/controllers/sync_management_controller.rb:170:in `inject'
  app/controllers/sync_management_controller.rb:170:in `sync_repos'
  app/controllers/sync_management_controller.rb:77:in `sync'
  lib/util/threadsession.rb:77:in `thread_locals'