adjust dependencies ffmpeg dependencies

Binary package hint: mythexport

Hi,

due to the ffmpeg transitions, the library names have changed from -unstripped- to -extra-.

Please adjust the following dependencies:
libavcodec-unstripped-52, libavdevice-unstripped-52, libavformat-unstripped-52, libavutil-unstripped-49, libpostproc-unstripped-51, libswscale-unstripped-0

(s/unstripped/extra/g should work).

While the -unstripped- packages are still provided by ffmpeg-extra, these are dummies to bring in -extra- packages, so it should still work, but the dependency resolver might have much less problems with the updated dependencies. (and -unstripped- will go away most probably after karmic).

Thanks,
  Stefan.