Remove unused param 'conn' from ConnectionPool#release

activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb

@@ -364,7 +364,7 @@ def checkin(conn)
             conn.expire
           end
 
-          release conn, owner
+          release owner
 
           @available.add conn
         end
@@ -377,7 +377,7 @@ def remove(conn)
           @connections.delete conn
           @available.delete conn
 
-          release conn, conn.owner
+          release conn.owner
 
           @available.add checkout_new_connection if @available.any_waiting?
         end
@@ -425,7 +425,7 @@ def acquire_connection
         end
       end
 
-      def release(conn, owner)
+      def release(owner)
         thread_id = owner.object_id
 
         @reserved_connections.delete thread_id