Android: Fix loading from qrc

On Android < 4.1 our temporary file is discarded without checking the
content. With this change we just open the file and pass the fd to the
mediaplayer instead.

Change-Id: I9233822725d8987c572b2d0b598721cee886de80
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>