[FIX] bus: useless setTimeout call

Partial backport of master fix eb52156
Solving javascript error after refresh in ie9 `Error: useless setTimeout call (missing quotes around argument?)`

addons/bus/static/src/js/bus.js

@@ -14,7 +14,7 @@
         },
         start_polling: function(){
             if(!this.activated){
-                setTimeout(this.poll(), 1);
+                this.poll();
                 this.stop = false;
             }
         },
@@ -58,4 +58,4 @@
     // singleton
     bus.bus = new bus.Bus();
     return bus;
-})();
+})();