Redmine/6119

If the user overtly includes "cf_null" in their bundle sequence, we should not silently ignore it.
By rights, we should expect that they have actually used this name for a bundle.
I would be happier if this were a test-case against one of the ways that our bogus handling of empty strings can lead to a bogus "cf_null" showing up in the bundlesequence, that we'd better not take seriously.  See my comment on the RedMine ticket.  If there is (as I wish there were) no plausible way to cause "cf_null" to show up in the list other than overtly having it appear as a literal in the policy file, then we should not filter it out; we should indeed expect to find a bundle named cf_null.
A test that treats it as an error to do so is, IMO, a bad test - it tests that we're doing something profoundly wrong and calls that a good thing, instead of acknowledging what's wrong with it and fixing *that* instead.