invalidparammix/missingparam get the module prefix twice

dieUsage will call encodeParamName, which will already prefix the error code with the module prefix

E.g. for ApiViewFeedbackArticleFeedbackv5 (prefix afvf), this error code was
(incorrectly): afvfafvfinvalidparammix. Should be: afvfinvalidparammix

Change-Id: Ia351678b49e96ef58dce773331ebe9a1b3ebf824