Bug#734748: directory "version" mangling and $download-version

[Osamu Aoki]

Hi,

Debian Bug report logs - #557768
 please support directory "version" mangling
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=557768

Debian Bug report logs - #734748
 Please use $download-version whenever a recursive regex dir
 is being processed
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=734748

As I reviewed back-log of BTS, these 2 bugs may be combined.

Mangling sorting order is good.  Then if version matches with
$download-version specified, then change its priority to very high to
select it.

Currently, 0~0~0~0~0~0dummy is use as the lowest value, so let me think
about using zzzzzz as the highest one.

Osamu