avcodec/error_resilience: comment out unused assignment

Its not removed as the code which uses this is out-commented too.

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

libavcodec/error_resilience.c

@@ -1200,7 +1200,7 @@ void ff_er_frame_end(ERContext *s)
             const int mb_xy   = mb_x + mb_y * s->mb_stride;
             const int mb_type = s->cur_pic.mb_type[mb_xy];
 
-            error = s->error_status_table[mb_xy];
+            // error = s->error_status_table[mb_xy];
 
             if (IS_INTRA(mb_type) && s->partitioned_frame)
                 continue;