Android: fix retrieving metadata from assets, qrc and remote files.

We need the same logic as for the media player: local files and assets
must be loaded with a FileDescriptor.
Because of a bug in Android API level >= 14, remote files have to be
loaded in different ways depending on the version.

Task-number: QTBUG-40274
Change-Id: I6411b959064d22219cf981a4dc8f4f26cf16f65f
Reviewed-by: Christian Stromme <christian.stromme@digia.com>