Fix #3943: Eliminate legacy code for distributed memcached servers.

app/models/tag.rb

@@ -139,9 +139,6 @@ class Tag < ApplicationRecord
 
     def update_category_cache_for_all
       update_category_cache
-      Danbooru.config.other_server_hosts.each do |host|
-        delay(:queue => host).update_category_cache
-      end
       delay(:queue => "default", :priority => 10).update_category_post_counts
     end
 

app/models/tag_alias.rb

@@ -22,11 +22,6 @@ class TagAlias < TagRelationship
     def clear_all_cache
       TagAlias.clear_cache_for(antecedent_name)
       TagAlias.clear_cache_for(consequent_name)
-      
-      Danbooru.config.other_server_hosts.each do |host|
-        TagAlias.delay(:queue => host).clear_cache_for(antecedent_name)
-        TagAlias.delay(:queue => host).clear_cache_for(consequent_name)
-      end
     end
   end
 

app/models/user.rb

@@ -84,7 +84,6 @@ class User < ApplicationRecord
   before_create :encrypt_password_on_create
   before_update :encrypt_password_on_update
   after_save :update_cache
-  after_update :update_remote_cache
   before_create :promote_to_admin_if_first_user
   before_create :customize_new_user
   #after_create :notify_sock_puppets
@@ -172,16 +171,6 @@ class User < ApplicationRecord
       Cache.put("uin:#{id}", name, 4.hours)
       Cache.put("uni:#{Cache.hash(name)}", id, 4.hours)
     end
-
-    def update_remote_cache
-      if saved_change_to_name?
-        Danbooru.config.other_server_hosts.each do |server|
-          delay(queue: server).update_cache
-        end
-      end
-    rescue Exception
-      # swallow, since it'll be expired eventually anyway
-    end
   end
 
   module PasswordMethods