stream_edl: allow opening edl only from local resources

edl is complex and prone to errors. Also there is no good reason for
external network playlist to require edl use.

stream/stream_edl.c

@@ -14,4 +14,5 @@ const stream_info_t stream_info_edl = {
     .name = "edl",
     .open = s_open,
     .protocols = (const char*const[]){"edl", NULL},
+    .stream_origin = STREAM_ORIGIN_FS,
 };