Fixing Count queries where Paginator is set

When a paginator is set with query params, it produces queries like
`select count(*) from users limit 20 offest 20`. MySQL considers this to
be nonsensical and returns the Empty Set. This changes Count to take a
copy of the Query object and sets its pagination to nil for the purposes
of the Count query, leaving the original query unaffected.

I'm open to suggestions as to a better way to organize that test... I'm not thrilled with where that `dummyParams` type is located.