mike committed changeset [660]

Cut down on the number of redirects by using preferred domain at admin redirect.

Also, properly go to the admin directory with a trailing '/', where the server would send you anyway.

Example: Formerly, http://signage.rpi.edu would redirect to http://signage.rpi.edu/admin, which would redirect to http://concerto.rpi.edu/admin, which would redirect to http://concerto.rpi.edu/admin/. This does all that in one hop. At least I hope, because I can't test it directly.