AuthenticationToken will be ignored if the cookie value contains '@'

if the cookie value is something like "email=xyz@abc.com", HDFS will ignore the AuthenticationToken and reject the request.

2014-06-05 19:12:40,654 WARN org.apache.hadoop.security.authentication.server.AuthenticationFilter: AuthenticationToken ignored: org.apache.hadoop.security.authentication.util.SignerException: Invalid signed text: u

This is caused by fix for HADOOP-10379 Protect authentication cookies with the HttpOnly and Secure flags
it constructs cookie header manually instead of using Cookie class so the value is not double quoted.