Bug 37163: Fix the redirect after deleting a tag from an authority framework to load...

Bug 37163: Fix the redirect after deleting a tag from an authority framework to load the right page

When you delete a tag from an authority framework, we intend to redirect you
right back to where you were, on the same page of tags, but because we pick
the wrong variable to set searchfield in the URL, we send you to the first
page instead.

Test plan:
1. Without the patch, Administration - Authority types - in the row for
   CHRON_TERM Actions menu, MARC Structure
2. In the Search for tag: input, type 092 and hit Enter
3. In the row for 092, Actions menu, Delete, in the page that loads click
   Yes, delete
4. In the page you are redirected to, note that you are at Tag 000, and the
   URL is ?searchfield=&authtypecode=CHRON_TERM
5. Apply patch, restart_all
6. Type 092 and hit Enter, Actions menu for the 093 row, Delete, Yes, delete
7. Note that now you have gone to the page where 093 used to be, because
   the URL is ?searchfield=092&authtypecode=CHRON_TERM and you can just
   keep deleting 09x tags one after another

Signed-off-by: Sam Lau <samalau@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>