Remove unused PutBitContext.

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@14007 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/mdec.c

@@ -38,7 +38,6 @@ typedef struct MDECContext{
     AVCodecContext *avctx;
     DSPContext dsp;
     AVFrame picture;
-    PutBitContext pb;
     GetBitContext gb;
     ScanTable scantable;
     int version;