Bug 19113: Barcode value builder not working with numeric branchcode

The regexp for the value builder 'hbyymmincr' doesn't allow for numerics in the branchcode,
so the nextnum found is always 0 and multiple Add always generate the same barcode.
This simply allow for numerics within the regex.

Test
- It's a bit complicated.  You need
   - all your branchcodes to be numerics (01,02,71...)
   - all barcodes to already be a bunch of numbers
- Modify the syspref 'autobarcode' to hbyymmincr, the home branch + date one.
- Find an item in the pro-search,
- New -> New Item
- Click on the 'p' to have the value builder create the next barcode.
   - Without the patch, the query won't have found anything, so it'll suggest xxxxxx0001
- Click Add.  It reprensent the form to enter another one.
   - Click on the 'p' edit box, it'll offer you again xxxxxx0001
With the patch, it'll offer valid ones everytime.

Signed-off-by: David Nind <david@davidnind.com>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit db067d48ee)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>

C4/Barcodes/ValueBuilder.pm

@@ -48,7 +48,7 @@ sub get_barcode {
     my $month = $args->{mon};
     my $query = "SELECT MAX(CAST(SUBSTRING(barcode,-4) AS signed)) AS number FROM items WHERE barcode REGEXP ?";
     my $sth = C4::Context->dbh->prepare($query);
-    $sth->execute("^[-a-zA-Z]{1,}$year$month");
+    $sth->execute("^[-a-zA-Z0-9]{1,}$year$month");
     while (my ($count)= $sth->fetchrow_array) {
         $nextnum = $count if $count;
         $nextnum = 0 if $nextnum == 9999; # this sequence only allows for cataloging 9999 items per month