Client does not send session refresh if it is the UAS session refresher

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What steps will reproduce the problem?
1.Establish a chat or file session with the terminating client as session 
refresher, i.e. Session-Expires: <timeout_value>;refresher=uas
2.When sip session timeout expires, the terminating client does not send SIP 
refresh request

What is the expected output? What do you see instead?
The expected result is it should send a refresh request to refresh the session. 
 Currently, the client does not send session refresh request when it is the 
refresher.

What version of the product are you using? On what operating system?
2.5.11

Please provide any additional information below.
The UAS can have 2 roles, non-refresher or refresher.
However, seems it assumes UAS is always not the refresher.
In SessionTimerManager.sessionRefreshForUAS(), it only checks the timeout and 
terminate the session as a non-refresher, it doesn't not send session refresh 
if it's the refresher.

Original issue reported on code.google.com by mcd...@mcdull.us on 13 Mar 2014 at 8:30