Bug 21818: Replace AutoCommit flag with DBIx transaction in stage-marc-import.pl

Bug 21818: Replace AutoCommit flag with DBIx transaction in stage-marc-import.pl

Like it was done in Bug 18806.

Test plan :
Use stage-marc-import.pl with and without patch, with a matcher to find
duplicates

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit ff849fadbade8b72faec52284b58e6f5dd8a71c9)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>