Fix incorrect libxml fprintf, erroring on clang win x64

Fix incorrect libxml fprintf, erroring on clang win x64

R=thakis@chromium.org
BUG=https://bugzilla.gnome.org/show_bug.cgi?id=751410
BUG=82385
Committed: https://crrev.com/73a2484753cd6b2e4af673cd6dc752ba5b00c116
Cr-Commit-Position: refs/heads/master@{#335736}

[Nico, 2015-06-23 20:26:49]

lgtm, thanks!

[Nico, 2015-06-23 20:27:41]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-06-23 20:28:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1204813002/1

[commit-bot: I haz the power, 2015-06-23 20:37:17]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-23 20:39:25]

Patchset 1 (id:??) landed as
https://crrev.com/73a2484753cd6b2e4af673cd6dc752ba5b00c116
Cr-Commit-Position: refs/heads/master@{#335736}

[scottmg, 2015-06-23 20:47:28]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1202303002/ by scottmg@chromium.org.

The reason for reverting is: Broke cast android whatever that is.
http://build.chromium.org/p/chromium.linux/builders/Cast%20Android%20%28dbg%2....

[Stephen Chennney, 2015-06-23 20:56:52]

On 2015/06/23 20:47:28, scottmg wrote:
> A revert of this CL (patchset #1 id:1) has been created in
> https://codereview.chromium.org/1202303002/ by mailto:scottmg@chromium.org.
> 
> The reason for reverting is: Broke cast android whatever that is.
>
http://build.chromium.org/p/chromium.linux/builders/Cast%20Android%20%28dbg%2....

Broke the world, in fact.