Throw if the requested registry file doesn't exist
Created by: muffato
When a worker or beekeeper is invoked with a wrong reg_conf argument, there is no explicit warning / error message, only potentially an error about the reg_alias not being found in the Registry.
Registry::load_all already has a flag to require the file to exist. I merely enable it and we now get a much clearer error message.
This is a breaking change for people who use a url and an invalid reg_conf at the same time. Previously, there would have been no warnings about the invalid reg_conf, and the database would have been connected to via its URL. Now eHive is going to complain about the reg_conf,
Have you added/modified unit tests to test the changes?
Yes, but requires Ensembl/ensembl#408
If so, do the tests pass/fail?
Have you run the entire test suite and no regression was detected?