nixos/services.mediatomb: fix vlc reference

          <accept-url>yes</accept-url>

          <first-resource>yes</first-resource>

          <accept-ogg-theora>yes</accept-ogg-theora>

          <agent command="${libsForQt5.vlc}/bin/vlc"

          <agent command="${lib.getExe vlc}"

            arguments="-I dummy %in --sout #transcode{venc=ffmpeg,vcodec=mp2v,vb=4096,fps=25,aenc=ffmpeg,acodec=mpga,ab=192,samplerate=44100,channels=2}:standard{access=file,mux=ps,dst=%out} vlc:quit" />

          <buffer size="14400000" chunk-size="512000" fill-size="120000" />

        </profile>