avcodec/tiff: Avoid duplicating strings

Reviewed-by: Stefano Sabatini <stefasab@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/tiff.c

@@ -2029,7 +2029,8 @@ again:
             av_log(avctx, AV_LOG_WARNING, "Type of GeoTIFF key %d is wrong\n", s->geotags[i].key);
             continue;
         }
-        ret = av_dict_set(&p->metadata, keyname, s->geotags[i].val, 0);
+        ret = av_dict_set(&p->metadata, keyname, s->geotags[i].val, AV_DICT_DONT_STRDUP_VAL);
+        s->geotags[i].val = NULL;
         if (ret<0) {
             av_log(avctx, AV_LOG_ERROR, "Writing metadata with key '%s' failed\n", keyname);
             return ret;