Fewer normal user errors at LOG_ERR level

Globalcollect has one eight-digit error code that maps to a large
variety of validation errors. The two exact problems I am
banishing from the system error log, are both the product of users
typing something silly at a form hosted not on our servers. We do
want to know if we have failed to validate things we have control
over, but these two are completely out of our hands, and
excruciatingly common.

@TODO: Refactor such that the error processing is all in
getResponseErrors, instead of spread out across multiple functions
for no identifiable reason

Change-Id: If8d610cbf79c14a7e4fa488955a506229da3dfae