MDEV-8427 main.connect fails on ppc64el in 10.0 as of 1a8cf15d

Followup fix for bug#35074: update the second location where
max_used_connections is calculated (to be like the
first one).

sql/mysqld.cc

@@ -9404,7 +9404,7 @@ void refresh_status(THD *thd)
     Set max_used_connections to the number of currently open
     connections.  This is not perfect, but status data is not exact anyway.
   */
-  max_used_connections= thread_count-delayed_insert_threads;
+  max_used_connections= connection_count + extra_connection_count;
 }
 
 #ifdef HAVE_PSI_INTERFACE