snowenc: initialize edges

This fixes a regression caused by changes to the buffer initialization code.
Fixes valgrind warnings
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/snowenc.c

@@ -1671,6 +1671,11 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
             memcpy(&s->input_picture.data[i][y * s->input_picture.linesize[i]],
                    &pict->data[i][y * pict->linesize[i]],
                    width>>hshift);
+            s->dsp.draw_edges(s->input_picture.data[i], s->input_picture.linesize[i],
+                              width >> hshift, height >> vshift,
+                              EDGE_WIDTH >> hshift, EDGE_WIDTH >> vshift,
+                              EDGE_TOP | EDGE_BOTTOM);
+
     }
     s->new_picture = *pict;