Include util/thread.h before util/util.h in util/thread*.cc.

Having it the other way around was reported to cause build failures with
MSVC. The definition of WIN32_LEAN_AND_MEAN in util/mutex.h might be the
culprit, but it's clear that this solution works for @DThiebaud.

Fixes #53.

Change-Id: I66adc10e7260ec52be06dd1a68e9221ff1c5a3ca
Reviewed-on: https://code-review.googlesource.com/3530
Reviewed-by: Paul Wankadia <junyer@google.com>

util/thread.cc

diff --git a/util/thread.cc b/util/thread.cc
index b620105..d97f14b 100644
--- a/util/thread.cc
+++ b/util/thread.cc
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#include "util/util.h"
 #include "util/thread.h"
+#include "util/util.h"
 
 Thread::Thread() {
   pid_ = 0;

util/threadwin.cc

diff --git a/util/threadwin.cc b/util/threadwin.cc
index 7b431ee..d68f2c5 100644
--- a/util/threadwin.cc
+++ b/util/threadwin.cc
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-#include "util/util.h"
 #include "util/thread.h"
+#include "util/util.h"
 
 Thread::Thread() {
   pid_ = 0;