avcodec/smacker: Directly goto error in case of error

The earlier version did not error out directly in case an error happens,
because it would lead to a leak: An allocated array is only reachable
via a local variable at that time; it is only attached to more permanent
storage at the end. While it would be possible to add custom code for
freeing on error (instead of reusing the ordinary code for doing so),
this commit takes the opposite approach and attaches the newly allocated
array to its permanent place immediately after its allocation.

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/smacker.c

@@ -251,17 +251,18 @@ static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int
         err = AVERROR(ENOMEM);
         goto error;
     }
+    *recodes = huff.values;
 
     res = smacker_decode_bigtree(gb, &huff, &ctx, 0);
-    if (res < 0)
+    if (res < 0) {
         err = res;
+        goto error;
+    }
     skip_bits1(gb);
     if(ctx.last[0] == -1) ctx.last[0] = huff.current++;
     if(ctx.last[1] == -1) ctx.last[1] = huff.current++;
     if(ctx.last[2] == -1) ctx.last[2] = huff.current++;
 
-    *recodes = huff.values;
-
 error:
     for (int i = 0; i < 2; i++) {
         if (vlc[i].table)