Merge branch '6567-jailkit-backup' into 'develop'

jailkit wrong file backup'ed

Closes #6567

See merge request ispconfig/ispconfig3!1797

Author: Till Brehm

install/lib/installer_base.lib.php

@@ -916,7 +916,7 @@ public function configure_jailkit() {
 
 		if (is_dir($config_dir)) {
 			if(is_file($config_dir.'/'.$jk_init)) copy($config_dir.'/'.$jk_init, $config_dir.'/'.$jk_init.'~');
-			if(is_file($config_dir.'/'.$jk_chrootsh.'.master')) copy($config_dir.'/'.$jk_chrootsh.'.master', $config_dir.'/'.$jk_chrootsh.'~');
+			if(is_file($config_dir.'/'.$jk_chrootsh)) copy($config_dir.'/'.$jk_chrootsh, $config_dir.'/'.$jk_chrootsh.'~');
 
 			if(is_file($conf['ispconfig_install_dir'].'/server/conf-custom/install/'.$jk_init.'.master')) {
 				copy($conf['ispconfig_install_dir'].'/server/conf-custom/install/'.$jk_init.'.master', $config_dir.'/'.$jk_init);