sync to latest x264 git, field was renamed

Originally committed as revision 15337 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/libx264.c

@@ -162,7 +162,7 @@ X264_init(AVCodecContext *avctx)
 
     x4->params.i_bframe = avctx->max_b_frames;
     x4->params.b_cabac = avctx->coder_type == FF_CODER_TYPE_AC;
-    x4->params.b_bframe_adaptive = avctx->b_frame_strategy;
+    x4->params.i_bframe_adaptive = avctx->b_frame_strategy;
     x4->params.i_bframe_bias = avctx->bframebias;
     x4->params.b_bframe_pyramid = avctx->flags2 & CODEC_FLAG2_BPYRAMID;
     avctx->has_b_frames= avctx->flags2 & CODEC_FLAG2_BPYRAMID ? 2 : !!avctx->max_b_frames;