Allow `DistributedCache#delete` to not publish changes.

lib/active_record/connection_adapters/postgresql_fallback_adapter.rb

@@ -46,7 +46,7 @@ class PostgreSQLFallbackHandler
   end
 
   def master_up(namespace)
-    synchronize { @masters_down.delete(namespace) }
+    synchronize { @masters_down.delete(namespace, publish: false) }
   end
 
   def initiate_fallback_to_master

lib/distributed_cache.rb

@@ -128,9 +128,9 @@ class DistributedCache
     hash[k]
   end
 
-  def delete(k)
+  def delete(k, publish: true)
     k = k.to_s if Symbol === k
-    @manager.delete(self, k)
+    @manager.delete(self, k) if publish
     hash.delete(k)
   end