added test if backup directory exists before old files are tried to be deleted
added test if backup directory exists before old files are tried to be deleted

zammad/zammad,monotek/zammad,monotek/zammad,zammad/zammad,monotek/zammad,zammad/zammad,zammad/zammad,zammad/zammad,monotek/zammad,monotek/zammad,zammad/zammad,monotek/zammad