Bug 8743: ZOOM error when merging authority change to biblios

Bug 8743: ZOOM error when merging authority change to biblios

The merge fails and the following errors appear in the log:
[Sun Sep 02 23:38:10 2012] [error] [client 75.149.175.233] ZOOM error 25
"Specified element set name not valid for specified database" (addinfo:
"F") from diag-set 'Bib-1', referer:
http://****/cgi-bin/koha/authorities/authorities.pl?authid=3010
[Sun Sep 02 23:38:11 2012] [error] [client 75.149.175.233] Premature end of
script headers: authorities.pl, referer:
http://****/cgi-bin/koha/authorities/authorities.pl?authid=3010

Test plan:
1) Set dontmerge to "Do"
2) Find an authority that is linked to a bib record.
3) Edit the main entry of the authority.
4) Save the authority record.
5) Notice that you got a nasty error and the bib record was not updated.
6) Apply patch.
7) Edit the main entry of the authority again (you can just set it back
   to what it was to start with).
8) Save authority record.
9) Notice that there was no error, and the bib record was updated.
10) Sign off.

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>