Only schedule keep alive if not already there

src/net/java/sip/communicator/impl/protocol/jabber/OperationSetBasicInstantMessagingJabberImpl.java

@@ -244,10 +244,12 @@ public void registrationStateChanged(RegistrationStateChangeEvent evt)
 
                 // run keepalive thread
                 if(keepAliveSendTask == null)
+                {
                     keepAliveSendTask = new KeepAliveSendTask();
 
-                keepAliveTimer.scheduleAtFixedRate(
-                    keepAliveSendTask, KEEPALIVE_INTERVAL, KEEPALIVE_INTERVAL);
+                    keepAliveTimer.scheduleAtFixedRate(
+                        keepAliveSendTask, KEEPALIVE_INTERVAL, KEEPALIVE_INTERVAL);
+                }
             }
         }
     }