Move build configuration to root of repository.

This is in preparation for creating GYP build files for each platform.

BUG=https://code.google.com/p/google-breakpad/issues/detail?id=575
R=mark@chromium.org

Review URL: https://breakpad.appspot.com/1414002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1304 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/common/windows/common_windows.gyp

@@ -28,7 +28,7 @@
 
 {
   'includes': [
-    '../../client/windows/build/common.gypi',
+    '../../../build/common.gypi',
   ],
   'targets': [
     {