Without any parameter, dt_from_string should not raise a warning
message.
Test plan:
Verify that the test file t/DateUtils.t displays a warning:
Use of uninitialized value $date_string in pattern match (m//) at
Koha/DateUtils.pm line 58
if the change in dt_from_string is not applied (manually edit the file).
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
f63aaf2242