[PATCH] wininet: Use 64-bit size for contentLength.

[Daniel Lehman]

> strtoulW won't do what you want on 32-bit platforms.

looks like even 64-bit windows (at least win10) errors if anything but
DWORD-size is passed in.  and it fails on overflow if Content-Length
exceeds sizeof(DWORD).  i'll update and resend

thanks
daniel