win toolchain downloader: Don't omit hidden or system files.

win toolchain downloader: Don't omit hidden or system files.

Hashes for both the 2013 and 2015 toolchain don't change for me locally with
this change, looks like there are no hidden or system files in the toolchain.
(I tried with the "you are a googler" flow.)

No intended behavior change.

BUG=495204
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=295804

[Nico, 2015-06-23 03:01:13]

thakis@chromium.org changed reviewers:
+ scottmg@chromium.org

[Nico, 2015-06-23 03:01:14]

While writing the CL description I realized I might have to test other flows
too. Do I? If so, which ones and how?

[scottmg, 2015-06-23 03:59:39]

No, that's it. lgtm

The failure case is bad though (download, followed by immediate deletion if the
hash doesn't match) so maybe land at a nice time when we'll be around.

[Nico, 2015-06-23 19:42:42]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-06-23 19:43:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1200113004/1

[commit-bot: I haz the power, 2015-06-23 19:45:08]

Committed patchset #1 (id:1) as
http://src.chromium.org/viewvc/chrome?view=rev&revision=295804