Fixed to not show "Back" button on summary screen and fixed breadcrumb.

- Back button is to go back to summary screen, is displayed on sub-screens that are linked from summary screen.

UI PR #7401

for #6819

app/controllers/miq_event_controller.rb

@@ -30,6 +30,8 @@ def show_list
   end
 
   def show
+    @display = params[:display] || "main" unless pagination_or_gtl_request?
+    @lastaction = "show"
     @record = MiqEventDefinition.find_by(:id => params[:id])
   end
 
@@ -53,7 +55,7 @@ def breadcrumbs_options
     {
       :breadcrumbs  => [
         {:title => _("Control")},
-        {:title => _('Events')},
+        {:title => _('Events'), :url => controller_url},
       ].compact,
       :record_title => :description,
     }