Patch for nginx handling of X-Accel-Redirect URLs

[vitalif at yourcmc.ru]

> No.  The NGX_UNESCAPE_URI won't be sufficient, and it's in fact
> does the wrong thing: it will stop unescaping on first unescaped
> '?', thus preventing files with two question marks from working.

...And why is it wrong???
As far as I know, the first UNESCAPED '?' means the beginning of query 
string.
If you want to pass a link to file with two '??' in the name, just 
escape them and that's it.
(Tested the last patch which I've sent, and it allows access to such 
files)