Bug 19367: $biblio variable redefined in same scope in ISBDdetail

Bug 19367: $biblio variable redefined in same scope in ISBDdetail

The following warning is generated by ISBDdetail.pl:
my" variable $biblio masks earlier declaration in same scope
at ./catalogue/ISBDdetail.pl line 171.

This patch removes this unnecessary declaration, which removes the
warning.

_TEST PLAN_

After applying patch:

1) Check code compilation with "KOHA_CONF=/path/to/koha-conf.xml perl -c catalogue/ISBDdetail.pl"
2) Note the only message is "./catalogue/ISBDdetail.pl syntax OK"
2) On /cgi-bin/koha/catalogue/ISBDdetail.pl?biblionumber=1,
view the source of the page and verify that the Javascript
contains a holdcount e.g. "var holdcount = 0".

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>