Bug 18273: Do not insert authority if there already are duplicates in koha

Test plan:

1) Create an authority with a unique value in a searchable field, for instance a PERSO_NAME authority with 'BZ18273' in the 100$a field.

2) Create a second authority with the same value in the same field.

3) Export this second authority as iso2709 (Save -> MARC (Unicode/UTF-8))

4) Run bulkmarcimport.pl with the following parameters:
perl bulkmarcimport.pl -a --file=/kohadevbox/koha/auth-xxxx.utf8 --match='Heading,100$a' -l /kohadevbox/koha/bulk.log

5) Check in the log file and/or through search that a third authority has been added (despite using the --match option)

6) Apply the patch

7) Delete the 3 authorities and repeat step 1 to 4.

8) Check that a third authority has not been added (--match worked)

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 2e2fba91bf)
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 0acc0dffb1)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>

misc/migration_tools/bulkmarcimport.pl

@@ -352,6 +352,7 @@ RECORD: while (  ) {
             }
         } elsif ( $results && scalar(@$results) > 1 ) {
             $logger->debug("more than one match for $query");
+            next;
         } else {
             $logger->debug("nomatch for $query");
         }