It seems we need to change the main alsa configuration for this to work properly.

* Changing the user rc things like ogg123 on the command line would
  work, but other things weren't working (aplay, speaker-test, etc.)

* Changing the user rc, even though invoking ogg123 on the command line
  worked, it wouldn't work when being fork/exec'd from fppd.

* Changing the main alsa configuration file seems to fix the output for
  fppd invoked ogg123 sessions.