Bug 18672: Test for fixing overwriting creation date

Bug 18672: Test for fixing overwriting creation date

Use this test to highlight issue:
prove -v t/db_dependent/Virtualshelves.t

After applying patch for Koha/Virtualshelf.pm it should turn green

Signed-off-by: Lee Jamison <ldjamison@marywood.edu>
Works correctly according to test case. Passes QA Tools and the
indicated t/db_dependent/Virtualshelves.t unit test.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>