shm: fix PTS delay (fixes #7579)

(cherry picked from commit 6eaec7cb6995c4f7c7a12d3c9e9fd6b05a446230)

modules/access/shm.c

@@ -314,7 +314,7 @@ static int Control (demux_t *demux, int query, va_list args)
         case DEMUX_GET_PTS_DELAY:
         {
             int64_t *v = va_arg (args, int64_t *);
-            *v = INT64_C(1000) * var_GetInteger (demux, "live-caching");
+            *v = INT64_C(1000) * var_InheritInteger (demux, "live-caching");
             return VLC_SUCCESS;
         }