Update CyberSource configuration

Update the CyberSource configuration to use the newer API implementation by default.  This updates the configuration to match the changes in: https://github.com/edx/edx-platform/pull/4880

@feanil Please review.
I was thinking this would be safer to deploy, since every environment should have "CyberSource" already defined.  When we're ready to cut over, we can make "CyberSource2" the default.