Fix the channelwho unit test (should be improved really.)

channelwho/test/com/dmdirc/addons/channelwho/ConnectionHandlerTest.java

         when(groupChatUser.getNickname()).thenReturn("nickname");
         when(channelUserAwayEvent.getUser()).thenReturn(groupChatUser);
         when(channelUserAwayEvent.getChannel()).thenReturn(groupChat);
+        when(groupChat.getEventBus()).thenReturn(eventBus);
         when(groupChatUser.getUser()).thenReturn(user);
         instance = new ConnectionHandler(config, scheduledExecutorService, connectionManager,
                 "domain", connection);