Merge commit '0a729b50' into thread-next

This merge was particularly difficult. I finally resorted to delete the
symbol scope active flag altogether and replace its usage by other
means.

Also I had to update custom route attribute registration to fit
both the scope updates in v2 and the data model in v3.

filter/f-inst.c

@@ -878,8 +878,8 @@
 	bug("Unsupported attribute type");
 
       switch (da->type) {
-      case T_OPAQUE:
       case T_IFACE:
+      case T_OPAQUE:
 	runtime( "Setting opaque attribute is not allowed" );
 	break;