Bug 20778: (bug 19777 follow-up) Fix subscription deletion

Bug 20778: (bug 19777 follow-up) Fix subscription deletion

Caused by
  commit 666a1b276097785c2a7c33e718f26f5512b3d972
  Bug 19777: Move template JavaScript to the footer: Serials, part 3

TT vars should not be used in .js files

Test plan:
Delete a subscription, confirm you see the confirmation popup and that
the it deletes the subscription correctly after it has been confirmed.

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>