FIX: [droid] Do not define XBMC_TEMP, thus moving temp to user folder, thus external storage if avail

Main goal is to move xbmc.log to user folder, so that it is accessible.

Still a FIX, IMO, because:
1) temp, i.e. ever-changing files, should not be put on internal flash if possible.
2) this aligns droid with the other 'nix platforms