Allow erasing ipaDomainResolutionOrder attribute
Currently when trying to erase the ipaDomainResolutionOrder attribute we
hit an internal error as the split() method is called on a None object.
By returning early in case of empty string we now allow removing the
ipaDomainResolutionOrder attribute by both calling delattr or setting
its value to an empty string.
https://pagure.io/freeipa/issue/6825
Signed-off-by: Fabiano FidĂȘncio <fidencio@redhat.com>
Reviewed-By: Martin Basti <mbasti@redhat.com>