Add a goto for init failure instead of duplicate calls to ac3_encode_close().

Originally committed as revision 26030 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/ac3enc.c

@@ -1761,19 +1761,20 @@ static av_cold int ac3_encode_init(AVCodecContext *avctx)
     s->mdct.avctx = avctx;
     ret = mdct_init(&s->mdct, 9);
     if (ret) {
-        ac3_encode_close(avctx);
-        return ret;
+        goto init_fail;
     }
 
     ret = allocate_buffers(avctx);
     if (ret) {
-        ac3_encode_close(avctx);
-        return ret;
+        goto init_fail;
     }
 
     avctx->coded_frame= avcodec_alloc_frame();
 
     return 0;
+init_fail:
+    ac3_encode_close(avctx);
+    return ret;
 }