It's not entirely obvious how we should respond to multiple calls to logoff()

fired in such rapid succession that we have not completed processing the first
call before the next one comes in. We could do the cumbersome thing and keep
track of an _isLoggingOff state but that is so inelegant that I can't bear to
do it. I'd rather just cope in the Presents code and put the onus on the caller
not to do wacky things like this.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5296 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/client/Client.java

@@ -503,8 +503,10 @@ public class Client
         }
 
         // kill our tick interval
-        _tickInterval.cancel();
-        _tickInterval = null;
+        if (_tickInterval != null) {
+            _tickInterval.cancel();
+            _tickInterval = null;
+        }
 
         // ask the communicator to send a logoff message and disconnect from the server
         _comm.logoff();