D1: std.md5: corrections for the given example

[Stewart Gordon]

grauzone wrote:
> notna wrote:
<snip>
>> What do you wanna tell us? That
>>   while (auto len = file.readBlock(buffer.ptr, buffer.sizeof))
>> has to work and does not because it's a bug? And that's why you think 
>> a bug report should be opened?
> 
> Enhancement request to allow auto in while, to make it consistent with 
> if. (You can write "if(auto x = foo()) {...}")

The chance of an enhancement request being landed in the D1 line has 
always been small, and now it's even smaller.

Stewart.