Roll NSS from r244613 to r245298.

This pulls in 1 change:

r245298: Add SEC_SignData to NSS exports. (eroman@chromium.org) 

BUG=245025

Review URL: https://codereview.chromium.org/140763005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245394 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -55,7 +55,7 @@ vars = {
   # and V8 without interference from each other.
   "webrtc_revision": "5397",
   "jsoncpp_revision": "248",
-  "nss_revision": "244613",
+  "nss_revision": "245298",
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling swarming_client
   # and whatever else without interference from each other.