Fix the map generators to use the $r2db_hash_map global

nginx-map/wp-nginx-map-json.php

@@ -25,14 +25,14 @@ function backend_to_shard_id($backend) {
 // Print the blog -> shard_id map.
 function generate_shard_map($blogs) {
   global $wpdb;
-  $wpdb_hash = &$wpdb->hash_map;
+  global $r2db_hash_map;
 
   $shard_map = array();
   foreach ($blogs as $blog) {
     $blog_id = $blog->blog_id;
     if ($blog_id == 1)
       continue;
-    $backend_id = $wpdb_hash->lookup($blog_id);
+    $backend_id = $r2db_hash_map->lookup($blog_id);
     $shard_id = backend_to_shard_id($backend_id);
     $shard_map[$blog->domain] = $shard_id;
   }

nginx-map/wp-nginx-map.php

@@ -38,8 +38,8 @@ function backend_to_http_endpoint($backend) {
 // Print the blog -> backend map.
 function generate_backend_map($blogs) {
   global $wpdb;
+  global $r2db_hash_map;
   global $noblogs_master;
-  $wpdb_hash = &$wpdb->hash_map;
 
   printline('map $http_host $backend_noblogs {');
   printline(' default http://' . $noblogs_master . ':' . NOBLOGS_PORT . ';');
@@ -47,7 +47,7 @@ function generate_backend_map($blogs) {
     $blog_id = $blog->blog_id;
     if ($blog_id == 1)
       continue;
-    $backend_id = $wpdb_hash->lookup($blog_id);
+    $backend_id = $r2db_hash_map->lookup($blog_id);
     $backend_http = backend_to_http_endpoint($backend_id);
     printline(' ' . $blog->domain . ' http://' . $backend_http . ';');
   }