[Nvrec-open] Librte support removed

[Heikki L. <hol...@cs...>]

Librte support was unmaintained, non-working, and in my opinion 
obsoleted by ffmpeg. In order to clean up nvrec code base, support for 
librte has been removed from the SVN. Users needing rterec should use 
older releases.

-- Heikki Lindholm