[mythtv] Packagers: use system libudfread if available

[Scott Theisen]

Hello all,

See https://github.com/MythTV/mythtv/pull/411

Anyone know if libudfread is packaged with/as a part of libbluray on 
some systems?

The pull request also enables -O2 for C++ in profile and release 
compile-types.

Regards,

Scott