cope with duplicate external_ids (bug 836797)
Error if product is not a simulation (bug 837169)
Merge pull request #74 from kumar303/prod-access

Error if product is not a simulation (bug 837169)
Merge pull request #73 from andymckay/external-id

cope with duplicate external_ids (bug 836797)
Revert "cope with duplicate external_ids (bug 836797)"

This reverts commit d7bfb4d50168c481ce17206760ea7347582f5ab1.