FFusion: Don't crash if avcodec_open() fails
FFusion: Don't crash if avcodec_open() fails

Regression for a while (surprising that it didn't cause any bug reports).
Found by enabling VP8 without remembering to register the decoder.


git-svn-id: d8f21eb7283bfb39ebab2f8f9b4a259b233f9348@1314 621663c8-3916-0410-8f58-edc14a8543d5

mrvacbob/perian,mrvacbob/perian,mrvacbob/perian,mrvacbob/perian,mrvacbob/perian