freetz_download:
 * do not use [http://www.gnu.org/software/wget/manual/wget.html#Download-Options-1 -O file] while downloading files as it doesn't preserve server timestamps, keeping server timestamps is important in order to reduce traffic while updating freetz-mirrors
 * this commit actually reverts changes introduced in r11156, refs #2234


git-svn-id: file:///var/svn/freetz/trunk@12217 149334a1-2f27-0410-a3b9-fc62619ac1e6