Fix to work around rename problem on android.

Still doesn't work for renaming folders but renamed files are
recognised. Eg, copy a.mp3 to the device with name a.mp3.tmp,
and the music player won't find it. Rename the file normally,
to a.mp3 and the music player still doesn't find it.

This patch fixes that by instead of actually renaming it
copies the file and removes the original. (Thus much
slower as it moves the file off device and then back
to the device)

Atleast it made csync and rsync work for me, unison doesn't
seem to work as it copies the files to hidden directories
and then moves the directory.