vmimage utility can't fetch fedora image on s390x

[richtja]

Describe the bug
Fedora stores vmimages for x86 and s390x in different repositories. Therefore, Avocado vmimage utility has two Fedora providers. Fedora and FedoraSecondary. When you want to fetch Fedora images on s390x system with avocado vmimage get --distro Fedora the image won't be found. The reason for this is that Image.from_parameters method doesn't respect the current system architecture as default architecture.

Based on my investigation, it looks like that the issue is in here.