Follow-up to Ie3499d
My first pass at what became Ie3499d9f2 was to keep the exception for duplicate
registrations with conflicting parameters but downgrade to a warning if the
registration attempts are identically parametrized. I then removed the
exception entirely, but left the if-block, which does not make much sense, as
it means we pass over silently module registrations that set different
parameters, and throw a warning only when they are the same.