Bumping gyp deps version to 640 (639 failed on canary).

BUG=None
TEST=None
TBR=sgk

Review URL: http://codereview.chromium.org/195027

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@25654 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -34,7 +34,7 @@ deps = {
     "http://protobuf.googlecode.com/svn/trunk@219",
 
   "src/tools/gyp":
-    "http://gyp.googlecode.com/svn/trunk@639",
+    "http://gyp.googlecode.com/svn/trunk@640",
 
   "src/v8":
     "http://v8.googlecode.com/svn/trunk@2811",