Second part of the fix for #2071. An empty string "" was being sent t…

…o .bind() and when the events were being cleared it went in to an infinite recursive loop till memory was out. The test was !types in the function and changing it to types == undefined fixed the error.

src/event.js

@@ -102,7 +102,7 @@ jQuery.event = {
 
 		if ( events ) {
 			// Unbind all events for the element
-			if ( !types )
+			if ( types == undefined )
 				for ( var type in events )
 					this.remove( elem, type );
 			else {