Fix last push url in history

Fix issue in history that caused some states to be swallowed by pushUrl, after going back and then trying to update to the previous state.

public/js/icinga/history.js

@@ -139,8 +139,10 @@
                 icinga.logger.debug('History state', event.originalEvent.state);
             }
 
-            self.applyLocationBar();
+            // keep the last pushed url in sync with history changes
+            self.lastPushUrl = location.href;
 
+            self.applyLocationBar();
         },
 
         applyLocationBar: function (onload) {