WPDB: Reset connection status variables when the connection is closed.

Fixes #36240.



git-svn-id: https://develop.svn.wordpress.org/trunk@36997 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/wp-db.php

@@ -3116,6 +3116,8 @@ class wpdb {
 
 		if ( $closed ) {
 			$this->dbh = null;
+			$this->ready = false;
+			$this->has_connected = false;
 		}
 
 		return $closed;