Change cert download filename to include username.
Change cert download filename to include username.

charliemeyer/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,tcmitchell/geni-portal,charliemeyer/geni-portal,charliemeyer/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal,charliemeyer/geni-portal,tcmitchell/geni-portal