Bug 8180 - cataloguing/additem.pl plack scoping

$dbh needs our scoping when using "Add item" to prevent error
Can't call method "prepare" on an undefined value at /srv/koha/cataloguing/additem.pl line 88.

Test scenario:

1. start intranet with plack
2. select one Edit items on one record
3. fill in new item and click on "Add item"

Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>

cataloguing/additem.pl

@@ -37,7 +37,7 @@ use C4::Search;
 use MARC::File::XML;
 use URI::Escape;
 
-my $dbh = C4::Context->dbh;
+our $dbh = C4::Context->dbh;
 
 sub find_value {
     my ($tagfield,$insubfield,$record) = @_;