Fix a compiler warning

Change-Id: Ib096998906935e58f52393ea9ac082f69ada7023

vpxenc.c

@@ -1767,13 +1767,11 @@ static void test_decode(struct stream_state  *stream,
                         enum TestDecodeFatality fatal,
                         const VpxInterface *codec) {
   vpx_image_t enc_img, dec_img;
+  struct vp9_ref_frame ref_enc, ref_dec;
 
   if (stream->mismatch_seen)
     return;
 
-  /* Get the internal reference frame */
-    struct vp9_ref_frame ref_enc, ref_dec;
-
   ref_enc.idx = 0;
   ref_dec.idx = 0;
   vpx_codec_control(&stream->encoder, VP9_GET_REFERENCE, &ref_enc);