Mark $wpdb_reverse_backend_map as global, for noblogs-cli

db-config.php

@@ -14,4 +14,5 @@ include_once('r2db/db-backends.php');
 noblogs_load_global_dataset();
 
 // Add all the sharded blog databases.
+global $wpdb_reverse_backend_map;
 $wpdb_reverse_backend_map = noblogs_load_backends();