improve Download button for Acq.Media releases

app/views/acquired_media_releases/index.js.erb

@@ -1,3 +1,5 @@
 $("#acquired_media_releases").html("<%= j render(@acquired_media_releases) %>");
 $("form input[type='search']").val("<%= params[:query] %>");
 $("#acquired_media_releases_pagination").html("<%= j will_paginate(@acquired_media_releases) %>");
+$("#selected_releases_form").attr('data-releasable-ids', JSON.stringify([]));
+$("#total_entries").val(<%= @acquired_media_releases.total_entries %>);