Comment 2 for bug 1340920

The file is generated from these lines in curtin_userdata, so I expect we need to strip a slash somewhere:

{{if node.split_arch()[0] in {'i386', 'amd64'} }}
apt_mirrors:
  ubuntu_archive: http://{{main_archive_hostname}}/{{main_archive_directory}}
  ubuntu_security: http://{{main_archive_hostname}}/{{main_archive_directory}}
{{else}}
apt_mirrors:
  ubuntu_archive: http://{{ports_archive_hostname}}/{{ports_archive_directory}}
  ubuntu_security: http://{{ports_archive_hostname}}/{{ports_archive_directory}}
{{endif}}