fraps: fix memleak

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

libavcodec/fraps.c

@@ -114,8 +114,10 @@ static int fraps2_decode_plane(FrapsContext *s, uint8_t *dst, int stride, int w,
             else if(Uoff) dst[i] += 0x80;
         }
         dst += stride;
-        if(get_bits_left(&gb) < 0)
+        if(get_bits_left(&gb) < 0){
+            free_vlc(&vlc);
             return -1;
+        }
     }
     free_vlc(&vlc);
     return 0;