ITS#9116 LMDB: fix bogus error check in read-only txns

libraries/liblmdb/mdb.c

@@ -6448,7 +6448,7 @@ mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
 		/* Make sure we're using an up-to-date root */
 		if (*mc->mc_dbflag & DB_STALE) {
 				MDB_cursor mc2;
-				if (TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
+				if (!F_ISSET(mc->mc_txn->mt_flags, MDB_TXN_RDONLY) && TXN_DBI_CHANGED(mc->mc_txn, mc->mc_dbi))
 					return MDB_BAD_DBI;
 				mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, NULL);
 				rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, 0);