Fix alertmaneuer soft buttons (#342)

* Fix AlertManeuer soft buttons removal

Looks like there was an old HMI code which
was recently uncommented, however it is not
working as expected.
Child objects which were dynamically created were
not removed properly. Removal function has been
updated to make removal of child objects as it
should be.

* fixup! Fix AlertManeuer soft buttons removal

app/view/sdl/AlertManeuverPopUp.js

@@ -115,7 +115,6 @@ SDL.AlertManeuverPopUp = Em.ContainerView.create(
      * @param {Object} params
      */
     addSoftButtons: function(params) {
-      var count = this.get('softbuttons').removeAllChildren();
       if (params) {
         var softButtonsClass;
         switch (params.length) {
@@ -161,7 +160,10 @@ SDL.AlertManeuverPopUp = Em.ContainerView.create(
       }
     },
     AlertManeuverActive: function(message) {
-      var self = this;
+      this.get('softbuttons.childViews').removeObjects(
+        this.get('softbuttons.childViews').filterProperty('softButtonID')
+      );
+
       var params = message.params;
       if (params.softButtons) {
           this.addSoftButtons( params.softButtons );
@@ -170,6 +172,8 @@ SDL.AlertManeuverPopUp = Em.ContainerView.create(
       this.set( 'activate', true );
 
       clearTimeout( this.timer );
+
+      var self = this;
       this.timer = setTimeout( function() {
           self.set( 'activate', false );
           FFW.Navigation.sendNavigationResult(