Point group's issues atom feed to group

This was using the user dashboard atom builder template, not one for the
group's issues.

app/views/groups/issues.atom.builder

 xml.instruct!
 xml.feed "xmlns" => "http://www.w3.org/2005/Atom", "xmlns:media" => "http://search.yahoo.com/mrss/" do
-  xml.title   "#{@user.name} issues"
-  xml.link    href: issues_dashboard_url(format: :atom, private_token: @user.private_token), rel: "self", type: "application/atom+xml"
-  xml.link    href: issues_dashboard_url, rel: "alternate", type: "text/html"
-  xml.id      issues_dashboard_url
+  xml.title   "#{@group.name} issues"
+  xml.link    href: issues_group_url(format: :atom, private_token: current_user.try(:private_token)), rel: "self", type: "application/atom+xml"
+  xml.link    href: issues_group_url, rel: "alternate", type: "text/html"
+  xml.id      issues_group_url
   xml.updated @issues.first.created_at.xmlschema if @issues.any?
 
   @issues.each do |issue|