Remove add site if the app was installed

src/freedombone-utils-webadmin

@@ -115,6 +115,11 @@ function web_admin_create_installed_apps {
                     echo '    <div class="row">' >> "$appslist_filename"
                 fi
 
+                filename="/var/www/${local_hostname}/htdocs/admin/app_add_${app_name}.html"
+                if [ -f "$filename" ]; then
+                    rm "$filename"
+                fi
+
                 filename="/var/www/${local_hostname}/htdocs/admin/app_${app_name}.html"
 
                 { echo '      <div class="column">';