Update nss_revision to 159459

This updates NSS to 3.14 pre-release snapshot 2012-09-25, along with
https://bugzilla.mozilla.org/show_bug.cgi?id=795213 to fix a warning.

R=wtc
BUG=153281, 151692, 151927
TEST=none

Review URL: https://chromiumcodereview.appspot.com/11040061

Review URL: https://chromiumcodereview.appspot.com/11143026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162398 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -39,7 +39,7 @@ vars = {
   # and V8 without interference from each other.
   "webrtc_revision": "2918",
   "jsoncpp_revision": "248",
-  "nss_revision": "158129",
+  "nss_revision": "159459",
 }
 
 deps = {