Fix for big timestamps. Thanks Zed Shaw!

git-svn-id: https://oauth.googlecode.com/svn/code/python@1134 f7ae4463-c52f-0410-a7dc-93bad6e629e8

Author: leah.culver

oauth/oauth.py

@@ -514,7 +514,7 @@ def _check_timestamp(self, timestamp):
         """Verify that timestamp is recentish."""
         timestamp = int(timestamp)
         now = int(time.time())
-        lapsed = now - timestamp
+        lapsed = abs(now - timestamp)
         if lapsed > self.timestamp_threshold:
             raise OAuthError('Expired timestamp: given %d and now %s has a '
                 'greater difference than threshold %d' %