core: Fix trivial bug by reverting to upstream.

The mupen-core config file was not being saved in an appropriate
location. The ae hack did not put a '/' between the dir and filename,
so the config file was being saved to
  <sdcard>/Android/data/paulscode.android.mupen64plusaemupen64plus.cfg
rather than
  <sdcard>/Android/data/paulscode.android.mupen64plusae/mupen64plus.cfg

Also, the second ae-hack in the file doesn't seem to be necessary.