bug report - "New Blog Templates" needs check for non-existing menu

(note: this is not critical bug, can be fixed by user disabling Menu copying)

description: if blog template has "What To Copy To New Blog?" -> Menus checked but the blog used for template does not have menus following error is produced, as there is no check for binary "false" being returned instead of menu:

Warning: array_flip() expects parameter 1 to be array, boolean given in /..../wp-content/plugins/blogtemplates/blogtemplatesfiles/blog_templates.php on line 597

Warning: Invalid argument supplied for foreach() in /...../wp-content/plugins/blogtemplates/blogtemplatesfiles/blog_templates.php on line 603