fix report time helper

refs CNVS-12817

test plan 
 - specs should pass

Change-Id: I33e2e9c419de84e28ced1b28545121e022bf1360
Reviewed-on: https://gerrit.instructure.com/34211
Reviewed-by: Dave Jungst <dave@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Rob Orton <rob@instructure.com>
QA-Review: Rob Orton <rob@instructure.com>