Switch to VideoLAN's repositories for libdvdread and libdvdnav.

All our patches have been merged, and they seem
to be the only repos for these libs to see any
development activity.


git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@6002 b64f7644-9d1e-0410-96f1-a4d463321fa5