Fix duplicate packet init introduced by 7f9aaa4

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpegvideo_enc.c

@@ -1125,7 +1125,6 @@ static int encode_frame(AVCodecContext *c, AVFrame *frame)
     AVPacket pkt = { 0 };
     int ret, got_output;
 
-    av_init_packet(&pkt);
     av_init_packet(&pkt);
     ret = avcodec_encode_video2(c, &pkt, frame, &got_output);
     if (ret < 0)