Update DVDPlayerVideo.cpp

https://github.com/quasar1/boxeebox-xbmc/commit/db1fb741700a231bf1d627a2564dcf6adad2556c

This commit broke 'seekframe' for Boxee, we can live with that but it also made some video output 'judder'.
Depending on what file is played it was occasional or consistent.
Rather than revert the whole set of commits I singled out the changes to  xbmc/cores/dvdplayer/DVDPlayerVideo.cpp as being the culprit.

This is a temporary measure until someone with 'greater' knowledge comes forward to give a 'proper' fix.